Staying Power for Added Rewards

A few weekend events this month offered up rewards that seemed designed to encourage me to play.  Ironically, the side effects of this sugar rush sometimes leave me feeling even less inclined to try the content once the incentives have expired. 

• Two weekends ago, Marvel Heroes held an event in which certain terminal (think dungeon) bosses dropped four times the normal loot.   This event was actually inspired by a bug a few months back in which Kingpin summoned Electra and Bullseye to assist him as normal, but the game incorrectly considered the two adds as bosses and awarded loot accordingly, leading to much farming of Kingpin that weekend. 
  
  I typically don't spend much time in terminals, and when I do get a Legendary Quest sending me to one I almost always do the easier green difficulty so I can complete the quest faster.  During the event, I opted for the slightly harder red difficulty hoping for better rewards, did the scheduled bosses, and didn't get anything of note.  I guess this is a challenge that ARPG's face - when you're killing bosses every 10 minutes they can't drop loot that frequently, but having an experience like this one definitely sends the message that I shouldn't waste my time on harder difficulties. 
  
  
• SWTOR offered up double exp last weekend, which made it time to finally finish off my Sith Warrior.  The sad truth with SWTOR is that I'd pay Bioware a fair amount of money - possibly as much as I've spent on the game during sporadic subscriptions - if they just removed the gameplay and offered an interactive movie version of the story in which my character just wins all the fights after I've chosen my dialog.  I suppose double exp is the next best thing in that at least I don't have to do any side quests, but this also does NOT motivate me to get back into the game when the exp drops back down to the normal rate. 
  
  
• The Marvel Heroes event of the week (started on Thursday and runs through Thursday morning) offered up rainbows used to earn pots of leprechaun gold in honor of St. Patrick's Day.  The items aren't great for power gamers, but they're good for leveling alts, which is most of what I do in game. 
  
  Rainbows drop anywhere loot drops, and the best loot drop rates in the game are in a challenge mode called X-Defense.  This is the only mandatory group content in Marvel Heroes at the moment - random groups of five are assembled by the group finder, and the mode features infinite waves of increasingly tough foes until the group fails, with better loot for each wave.  The good news is that there was NOT a specific bonus to X-Defense this weekend, so what I saw was what I got.  The bad news is that ironically the rewards were perhaps too good. 
  
  I dusted off a character I wasn't really enjoying much in story mode and chewed through fifteen levels, gaining unique items (the game's top rarity) for three of my five gear slots and multiple duplicates besides.  People always swear that group content should be more rewarding than solo, and this definitely fit the bill.  And I didn't hate it, so that's good.  However, it's arguably so much better than playing the game the normal way that I've been playing it for the last three months that going back to story mode almost seems like wasting my time.  

I guess it's a hard balance -  how do you shake things up in a way that leads to sustained interest in something the player has not been doing, rather than a one-time blip and disappointment thereafter?