First, let me say I love this map, have loved it since waugriff's days and COT 1, and I have enjoyed the new chaos stuff when I got back into Wc3 recently. I also want to make mention that I like difficult maps and challenges, so I'm not whining about how hard this is. That said, this map has always had a big issue with scaling, most abilities are completely useless, as in shouldn't even have a point in them past lvl 10, including most Ultimates. Why? Scaling. That lvl 4 shockwave doing 4000 damage just isnt much use on mobs with 100k hp, best not even to stop swinging to use it.
The one example I've seen where this Isn't the case is the Phoenix ranger's Agility-based skill, and on a sidenote, the only lvl 900+'s i've seen were phoenix rangers. >8(
The only way to fix this is to make all abilities scale based on stats and level. It makes most heroes COMPLETELY useless.
Other thoughts:
Another possibility, is to scale the entire game down in terms of stats, sure, +1,000,000 damage items are fun to look at, but its not essential, make everything a lot weaker so your dealing with Thousands not millions or billions, its less complicated, and provides less of a 'growth spurt' in terms of an early hero getting a item that suddenly makes him godlike versus other heroes of his level, like a +60 stats item, which are common.
You could still make the gods godlike, the demons demonlike, bosses just as strong, comparatively, etc. Just scale down on all the big numbers, its a headache.
