Been in the last 2 stress test/beta weekends of SW:TOR (Yay!) and here are my impressions.
While it doesn't break the mould (neither did WoW tbh), focusing more on story does make a huge difference to the experience. You're part of a bigger story and the fact that you can make some decisions (small as they might be) involves you more & makes your story more personal. The flipside is that so far (up to lvl 25) it's been very linear, so (same-faction) alts will go through all the same (side) quests, though the class quest driving the main story will be totally different.
They've really succeeded in transforming their single player RPG's into an MMO: the dialog options & excellent voice acting make you more involved in those quests and I didn't find myself skipping quest text & just heading to the waypoint like I do in other MMO's. There's also bonus quests that pop up while questing to kill a certain number of mobs for extra XP (they can be ignored) and some even have multiple layers which eventually leads you to kill an elite.
While the game can sometimes feel like you're playing a single player game (along others playing their single player game) there's enough incentive to group: heroic quests, flashpoints, PvP, ... Heroic quests are just group quests while Flashpoints are story-driven dungeons. Only played 3 (the first 2 Republic ones & the first Empire one), but they've all been fun and they do promote teamwork.
Haven't done any PvP, so can't comment on that.
Crafting feels really weird at first (your companion crafts & is sent out on collection missions) as it's slow (crafting an lowbie item takes a minute). But once you pick up more companions, they can craft while you're out with another companion doing quests, etc. So you won't sit in town for hours crafting instead you can do whatever while your inactive companions craft. Supplies are also available in good amounts, never had to go out of my way for mats, got more than enough just questing.
Combat is actually more like CoH than WoW really (Yes!) in that you usually fight groups of mobs and there's no autoattack. It makes combat more active &fun imo. While resource management (mana/energy/power) isn't an issue while questing as mobs die fast, in drawn out fights (heroics, flashpoints and PvP I guess) it adds a nice dynamic without feeling overly restrictive and you always have a basic attack to deal some damage & regain some mana/energy/power.
All in all SW:TOR has me really excited, the story based gameplay makes levelling a joy, so there's a lot of fun to be had on the journey to 50. Not sure how it will be end game, but there will be hard mode dungeons, raids & PvP, again nothing ground breaking. I just hope they will add new content (new planet(s) with associated quests) every few months instead of just adding new raids, but well see. Meanwhile there's enough to do & fun to be had on the way to endgame

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