Gut check: how reasonable and fun is Titania these days? I know it'd be good in my environment. It's been on my personal "banned" list for years....but my format's speed is picking up, removal is getting a bit better, and
Multani, Yavimaya's Avatar is feeling a little clunky.
...
It's definitely my type of card.
Yeah, I "banned" it and then ended up un-banning it once my power-level had advanced by enough. It's an absolute bomb, but in my format that's what you should expect at 5 mana. You need to meet certain land/creature ramp criteria to make a 5 drop playable once the speed gets high enough - in fact, I think Titania and Yorion are the only creatures you cast for 5 mana in my entire cube. Then once you resolve it, you basically always get value and extra power left over even if they remove it so it's worth it.
Some percent of the time you
really go off and kill them on the spot. In the original version of the Mox Cube this created a bit of problem where BG duress + wasteland + Titania/Zuran Orbs had the best disruption and the best combo kill. At that time, cutting Titania was 100% the correct decision. But now that everything else has caught up in power and the speed has increased so much, Titania is fair + sweet so its an easy include.