For any full tank champion tenacity is bound to be at least 50% with masteries and even more in case of mundo or if you're wickd and playing irelia.
When you're in a situation of being a zero mobility squishy mid laner and there's a shyvana/mundo/olaf, who have 3k hp and very likely a banshee's, running at you, you're forced to use whatever means you have to peel them off yourself. And since you dont have any mobility but your main role is still to delete the carries, you're kind of in a position where you're not doing what you should be in a teamfight because you can't just run past a few champions and expect to not die or go low in the process. On the other hand champions with mobility allow to dash around cc or the enemy front line right to the carries and go in and out of the fight when needed.
I mean it's all still very situational obviously, but veigar in general would have a much harder time in mid-late game teamfights given they're somewhat coordinated by both teams. Unless of course it's past the point in the game where his q scaling hasn't yet reached beyond reasonable limits
You can compare veigar to syndra in that sense, except her scaling is obviously more limited but she has more aoe early on and her damage in general comes earlier in the game, she's had much more success than veigar the few times she has been picked competitively but people still don't value her all that much just because in terms of mobility all she can do is run while her flash is on cooldown
just like i wish somebody actually played ad offtank(not trinity force) malphite even tho he sucks until 6 items l0l
Last edited by leyz; Feb 23, 2014 at 06:58 AM.