Dantooine
So far, the only one of the planets unveiled that had been in any of the KOTOR games is Korriban, which appeared in both Knights of Old Republic games. However, one other planet appeared in both games, Dantooine.
Dantooine is characterized primarily by its grasslands, rivers and lakes, and its population of mostly farmers. Unlike the core planets, Dantooine has little or no industrialism and a fair amount of wilderness. In the first KOTOR game it appeared primarily as the home of the Jedi Enclave, and in the second one with the enclave in ruins. The settlers on Dantooine were historically protected by the presence of the Jedi Order, but by the time The Old Republic game begins, Dantooine could potentially be under Sith control, making it an extremely different place.
Tatooine
The most iconic part of the Star Wars universe is almost certainly the sandy hot land under two suns full of Moisture Farmers, Hutts, and hunters. Appearing in five out of the six Star Wars movies, and one of the KOTOR games, its been seen in more media than nearly any character, except Obi Wan, C3PO, R2D2 or Vader.
Amongst the outer rim Star Systems, Tatooine is populated by some of the hardest working, and the laziest, people in the galaxy(Moisture Farmers and Hutts respectively). During the Old Republic time period, the main colony of Tatooine was the Anchorhead settlement, where swoop racing and beast hunting were the biggest parts of the Czerka run economy, and conflict with the Sand People was a constant concern. Whether or not this will be viable to be implemented in ToR remains to be seen, but Id love to bulls-eye some womprats in my T-16, or at least its 3000 year old predecessor.
Kashyyyk
The Wookiee home world may have only appeared in one movie(not counting the Star Wars Christmas Special), but the idea of venturing into the horrifying Shadowlands is one that should excite and scare all Star Wars fans, as walking amongst the trees and talking with walking carpets.
The mid-rim planet of Kashyyyk includes around seven levels of woshyr tree buildings, the seventh level being where the majority of the Wookiee culture resides. The majority of Wookiees and/or adventurers would rarely be seen going beneath the fourth level, and much less running around on the savage ground level, called the Shadowlands. During the Old Republic time, unless more lore has been added or changed, they would be a free group, who had thrown off the shackles of the Czerka Corporation.
Manaan
The entire economic point of this Selkath planet, to the rest of the known galaxy, was to export Kolto, to precursor to bacta. By the time The Old Republic takes place, Bacta has been discovered, and the need for Kolto has disappeared. It is very unlikely that this planet will make an appearance, and if it does it will most likely be full of barbaric Selkath living in their planets oceanic surface.
Rakata Prime
The "Unknown World" of KOTOR, Rakata Prime was the homeworld for the Rakata species and their infinite empire, but after their fall, the point of such a planet in this game seems nonexistent, unless to serve as a raid encounter or something of the like.
Taris
The roaring metropolis planet on the outer Rim, Taris was an over populated, plagued by poverty, and the site of a "rakghoul" plague. Then the Republic and Sith clashed over it and Darth Malak bombed it into oblivion. But what of it now?
By the time of the Galactic Civil War, Taris had been rebuilt, at least mostly, but the player could still be looking at a planet covered in ruin and death, inhabited by a few ardent survivors. Theoretically, everyone on the top levels died within a few seconds of the bombardment. Yet some, including Calo Nord, survived, as did at least a few on the bottom of the city where the Rakghouls roam. The idea of revisiting a planet, that was once a big urban center, as a ruined wasteland seems very plausible and interesting for Bioware to implement, perhaps as a sort of raid, or zone that could be accessed via a space station.
Telos
Another outer rim planet covered in urban sprawl, Telos was also bombed by the Sith fleet under Saul (Carth Onasi's former mentor) and then a secret Jedi Academy was built on the northern iced-pole of the planet.
The planet from which Carth Onasi hails was once a lush beautiful planet. With the work of Ithorian Renovation project it's theoretically on its way back, and would be in a recovery stage just before the time of the Old Republic. Canonically the planet completely recovers by the time of the Galactic Civil War. However the Jedi Academy that would have existed there under Atris may have become unimportant by this time.
Onderon
In case, for some reason, Tatooine isnt enough of a desert for one, there is always the planet of Onderon. It appears to be an ancient desert with an architecture that is almost Egyptian.
The surprisingly backward society of Onderon existed throughout the Jedi Civil War and was in fact victorious against Mandalorians who ended up settling on their jungle moon, Dxun. The population of Onderon was divided into two main groups, Beast Riders and the civilized people. If a "Beast Master" type class is implemented this planet may well become part of The Old Republic, otherwise it is unlikely.
Dxun
Unlike the previously mentioned objects Dxun is a moon, rather than a planet, and it orbits Onderon.
Home to a small band of Mandalorians in the Second KOTOR game, the moon possesses a great amount of wildlife, much of which is extremely dangerous. This moon has plenty of Dark Side energy about it, and very well could be seen to have a cameo, or maybe a larger role in SW:TOR.
Nar Shaada
The so-called "Smugglers Moon" orbits the already unveiled Nal Hutta, with cities that have sprawled the surface for millions of years, and have always been polluted, filthy, and corrupt.
Gang controlled, this city may be similar to Couruscant and Taris in construction, but thats where the similarities end. After the trade routes moved away from Nar Shaada around 4,000 BBY the Evocii (original race of Nal Hutta) were forced into slave labor in the cruel undercity of Nar Shaada, and the moon found new prosperity as a center of criminal activity, namely with the organization called the Exchange. With Nul Hutta making an appearance, this planetoid seems a likely addition.
Alderaan
Alderaan barely appeared in the films, but was mentioned and destroyed. Whatever was on that planet would never be explorable again... unless of course it was Alderaan 3,500 years before its destruction.
Of course the description of this planet as a beautiful, peaceful and unarmed planet sounds amazing, but may not fit as a planet in an MMO. The culture of Alderaan praises education, higher learning and participation in the Galactic Senate, but the planet is canonically a place of constant border wars and skirmishes during this time period. Hopefully BioWares got something up their sleeve for Alderaan because it would be amazing to finally explore.
Yavin 4
This moon over the gas giant Yavin has more of a purpose than just hiding the Rebel Base in A New Hope, various Sith lords, warriors, princes, assassins, tombs and relics litter the surface. Perhaps this could be implemented as a leveling or questing zone rather than as a whole planet.
This list is only a small fraction of the planets in the known Star Wars Galaxy, but each are special because of the place they hold in the history of the IP. As we get new information from BioWare, it will be interesting and exciting to see each world they unveil. While there may certainly be new and unusual planets created solely for The Old Republic, hopefully we will be able to revisit some of those we already knew about while questing in a galaxy a far, far away.
Sourceshttp://starwars.wikia.com/wiki/Dantooinehttp://starwars.wikia.com/wiki/Tatooinehttp://starwars.wikia.com/wiki/Kashyykhttp://starwars.wikia.com/wiki/Lehonhttp://starwars.wiki.com/wiki/Tarishttp://starwars.wiki.com/wiki/Onderonhttp://starwars.wikia.com/wiki/Dxunhttp://starwars.wikia.com/wiki/NarShaadahttp://starwars.wikia.com/wiki/Alderaanhttp://starwars.wikia.com/wiki/Yavin_4