Up up and away

@Conred  
No clue on the second one, but as for Tirek, Discord likely didn’t have the ability to do anything until the Rainbow Power had been unlocked, at which point everything was fixed anyway and why risk re-losing his powers by screwing up the timeline? Let’s go crash Twilight’s housewarming party instead. That might be fun.

@Sr Pelusa  
Omg I read the first one of that “Q messes with the jj Abrams Kirk” comic and it made me squee so hard you don’t even understand fangirling intensifies

And then both parties collide in the IDW Multiverse:
 

@Background Pony #A688  
Maybe because of the mirrors, all timelines are fixed. I mean this is a show that has a lot to do with destiny. Not to mention ‘It’s about Time’ didn’t changed anything. Just became a fixed time loop.

@zabchan  
That’s what’s exciting me three most about this; I loved the Discord and CMC FF, so it’s really nice to see them hang out again.

@Background Pony #F19E  
well that make sense  
Good Sombra universe could just be an universe when someone traveled in time and changed Discord into good guy or something

@Derpinator  
Carlos he can get stuffed

@Derpinator  
Discord!

@FanOfMostEverything  
And Carlos.

And then Discord was Miss Frizzle. And the Bus.

Discord taking care of 4 girls. THATS interesting!

@Conred  
I would say that he couldn’t because of time paradoxes. If he warned himself about Tirek and took precautions than he never would have needed to travel back and time and therefore paradox would form. Or…something like that.
 

@Turkleson  
i think the hwole dimension mirrors is the answer. perhaps he realized that he was not traveling to his own world’s future, and there was multiple thus alternate realities. the spell was ultimately, and forevermore, a failure if he cannot necessarily see his world’s future, yet it inspired him to travel to another one.
 
traveling to the past and changing it would only either create a destined event, like twilight did to herself, or simply create a new world yet leave your own unchanged. this is not necessarily scientific time travel, it is magical. though discord can twist the rules far more than normal magic users can we must include.

@Conred  
guessing the reason is because it would do no good. it might create a timeline where he was prewarned, but it would not prevent make his world non existant. the whole alternate dimension thing seems to indicate that. more than likely traveling so far into the past would not have any knowable or significant effect on the timeline, and the timeline is more maleable when magic is involved.
 
also when it comes ot timetravel, considering what he consdiers his greatest invention is the dimension mirrors, i would guess he was incorporeal when he did it and, also, discovered that in fact there were multiple futures at some point thus alternate realities. so he could not have too clear a vision of the future cause it could be the future of an alternate world or, perhaps even, the present of that alternate world, and not his own.  
fact remains that the spell does not seem to exist in the library, if pinkie never found it, and that it was lost to the ages, like his portal magic.

@Turkleson  
So why Discord just didn’t travel in time to stop Tirek or warn himself about betrayal? Why didn’t he time travel in Return of Harmony to stop the Princesses when turned him into stone?

@Background Pony #F19E  
Well according to the ‘Journal of the Two Sisters’, which was written by Amy Keating Rogers so it’s likely canon, Starswirl perfected Time Travel and had used it on many occasions. The Spell Twilight found in “It’s about Time” was just the beta. If he can do it, so can Discord.

Fezzes are cool!  

travel in Space and Time?
 

if nothing else, I wanna see discord spend more time with his comic-canon friends, the cmc

Who cares about time travel?
 
MORE FLUTTERCORD! (They will also have to show responsobility with taking care of 3 fillies, like parents xD)

This is going to end terribly…
 
I love it!

I don’t know how anyone can say that Discord being able to time-travel seems like it’s “pushing it” when Twilight’s done the exact same thing in It’s About Time. True, she just went back a week for a minute, but given the power level of Discord, going even further back for a longer a period of time shouldn’t be that hard.  
And of course, as someone else already mentioned, he’s already brought himself and Twilight back a few hours in Return of Harmony. They were like spirits though, and I’m assuming they’re all going to be corporeal in this story.

@PonyPon  
Sounds like a winning combo to me. ;)