I tend to play Solo-Top Nasus rather often, as he is my main for soloing up there. I can openly say if I was to really, really sit back and think about my issues I have with him. It is one very, small, simple thing.
Its his Q.
His Q is beautiful, I love the way it can just keep building damage, however it /can/ take forever to farm it up. If they /had/ to do a rework on him, I would just like that boosted up to maybe +6 every last hit or something a bit higher then +3.
I have no problem with his W, as it is a beautiful way to play catchup with someone, then if they are still pulling away, I tend to just exhaust them. I actually know how long I have mentally before I need to use Exhaust by this point. XD
I actually like E. The problem is, it is hard to get people to /stay/ in E. E is a great anti-tank measure as it tends to rip away their armor while they are standing in it. Its actually fun to throw E in when Jarvan decides to arena you, because no he is losing armor, taking damage. You hit R and your just giving him a murder smile, while you lifesteal + Q away.
Or you can toss in E when one of you team mates gets trapped to help them nom on his armor. So I do like E, I just wish if you threw it down they maybe get stunned locked for a few or again, slowed.
Maybe trade is Wither (W) for a Stun and his E as an area effect Slow/Armor break down?
R is beautiful. It doesn't need any changing.
And most importantly!
...even if he got new artwork, they better not change his voice. The man behind the voice for Nasus is no longer with us and honestly, I love the way Nasus sounds. He has a beautiful voice.