One of these is the daily quest. If you set aside the unnecessary loading screens courtesy of the personal starship system, SWTOR has a perfectly functional daily quest system. In fact, these quests offer large quantities of credits that can be used to unlock the pricey-sounding Legacy perks. These sorts of incentives are precisely the sort of thing I used to work towards in other MMO's, but in SWTOR I have yet to run a single daily quest.
World of Warcraft added daily quests in the content patches of the Burning Crusade expansion, starting in mid-2007. Previous reputation grinds had allowed players to choose the rate at which they advanced, while daily quests remove player choice by dictating how much progress is allowed each day. The game may offer you other things to work on - Blizzard plans to offer approximately 48 daily quests across half a dozen factions each and every day in WoW's new expansion along with expanded non-daily options - but you will advance no further towards any given objective until tomorrow.
Back in 2008, I was doing daily quests despite mostly the same objections. At the time, having access to multiple MMO's was generally going to cost you multiple monthly fees. Today's non-subscription payment models make it that much easier to simply switch to another game after collecting whatever low-hanging daily fruit I'm working on. I've started many daily quest chains - WoW's get more intricate with each patch - but continuing to repeat the content is less attractive when I could be doing something completely new in a different game.
I'm not convinced that Blizzard's brute force approach - earmarking over a quarter of the quests in the upcoming expansion as dailies to offer greater variety in the random pool - will solve this problem.
(Aside: I don't mean to over-emphasize one aspect of the daily quest, as there is quite a bit more - good and bad - that daily quests accomplish. There are social advantages to encouraging players to sign on daily, though these can become disadvantages if the incentives tell players not to help their guildmates until after finishing their personal daily quest quota. There are also potentially strategic choices to be made in what to go after first if the limit on quests - which WoW will no longer have - is low enough to be meaningful. Finally, extending the real world days required to finish the grind has obvious implications for games that charge a monthly fee, which was almost all MMO's back in '07.)