In season 3, you nerfed Nasus' sustain because he was too safe
This was at the end of season 3, when Doran's shield had been buffed giving a massive 10hp/5, and Nasus had 14% LS at level 1 and would run Lifesteal quints and have 20% LS at level 1. On top of this, meta top laners were Shen, Zac, Vlad, Renekton, Trundle, Mundo, etc. Aside from Renekton, all of these match ups were extremely easy and couldn't really stop you from farming.
You nerfed his Lifesteal to 10% at level 1, at the time I agreed with this change. Nasus was way TOO safe. He was outsustaining hard counters like Darius and even Olaf. But then you went on to nerf D-shield and Lifesteal quints but Nasus wasn't impacted much because top lane was garbage, everything sucked so instead Of being balanced, Nasus was just made weak like the rest so he still was getting farmed. Because of this, you went on to gut his spell range on wither and remove his bonus casting ranges on his ult because you basically had the stance that Nasus would get farmed regardless so you were "enhancing" his weaknesses, aka removing other strengths he had.
It's time to do this with Veigar. Veigar is way too fucking safe and his scaling is 10x better than Nasus' is because it applies to his AP while also having access to multiplicitive scaling, something Nasus doesn't have since Nasus doesn't have AD scaling outside of Q. Nasus can't even scale his farm, Veigar can. Not to mention, Veigar has amazing ratios and can farm from 950 range, which trumps any sustain or durability Nasus has ever had because 950 range > 150 range and it's not even close.
You need to either make Veigar less safe and reduce his Q range back to 850 or you need to make him weaker in other areas. In reality, Veigar is still pretty prone to being dove until he buys Zhonyas, so there's not much that you could change there to make him weaker on that regard. Another change is nerfing ratios but he is still a Mage and mages life and die off of their ratios, so I'm not sure that's a good idea either. There is the prospect of removing the % damage his ult does of his enemies AP, but even then that's hardly an issue because at the point where his ults %AP damage is doing absurd damage, an enemy Mage likely has zhonyas and can simply use zhonyas to soak his ult and put it on CD without taking damage. So in reality, there is one option here and that's to make him less safe, reduce his Qs range back to 850. I'm fine with all the other buffs because they make him a bit more consistent and reward him for interaction, which is a good thing imo.
Some people will point out that TP is to blame but I'm going to be honest, with champions like Nasus and Veigar, their lane or their scaling, is won or lost by the first few times they back and TP back to lane. A CD nerf to TP doesn't suddenly make that any less true, so nerfing TP likely doesn't change anything in that regard, it would just mean they can't consistently TP to other lanes, which Veigar almost never will do. So even then, a nerf to TP does nothing to reduce his safety, short of removing it which isn't an option nor should it be.
Now, I already know what's coming next: "wow HateDaddy omg Nasus builds full tank and has sustain, Veigar doesn't wowzers Nasus is way better in every way you fucklord!" Yeah no, being ranged is the best defensive steroid in this game, especially when you have access to zhonyas and you have long range on spells to boot. Farming in melee range is never as safe as farming from 950 range, regardless of how you build or how much sustain you have. Nasus also doesn't have AD ratios, meaning he has no scaling for his Qs damage other than sheen procs/Trinity procs and outside of that, he can't afford to build anymore damage because he's melee and immobile, so he's not even likely to get his farmed damage off on priority targets, Veigar is. So please don't pretend that Nasus is somehow way safer because this board circlejerks that immobile mages with their long range and waveclear are inherently weak and never viable, which is hilariously wrong and stupid.
Bottom line is this, Veigar is too safe and I'm fine with the rest of his power, he just needs to be less safe in lane. Let the downvotes begin.
: Just cc him and blow him up. He's and immobile mage and easy to gank and focus in team fights
: HER DAMAGE IS STUPID OP! SHE IS SUPER SAFE AND YOU CAN NEVER GET TO HER AND HAS THE SAFEST LANING PHASE! SHE CAN FARM FOR FREE WITH HER RIDICULOUS RANGE AND INFINITE MANA
make him useless
potential infinite scaling with chimes, requires roaming, more or less tacked on to make auto attacking even worth using, cannot itemize to increase chime count, has minimal impact on power budget
potential infinite scaling on Siphoning strike, requires last hitting from 150 range with a specific ability with a cooldown, scaling impacts one ability and does not directly impact survivability, cannot itemize to increase siphoning strike stacks massive chunk or power budget
potential infinite scaling on HP, requires last hitting a minion or getting a kill/ assist on champions, naturally builds HP, one ability scales with HP, medium chunk of power budget
potential infinite scaling with ability power and armor, requires minions to die near thresh, damaging abilities scale with AP, no armor per level, low base armor, improves passive component of e, can build armor and AP, small chunk of power budget