Okay here are my comments:
Omniknight: Sorry, but current one sounds a lot cooler and less generic.
Sven: Rogue Knight is really unfitting, but I don't like Divine Warrior that much.
Anti-Mage: Why a name change? Current one is perfect. Mage Slayer sounds worse Imo.
Juggernaut: Juggernaut - Wikipedia, the free encyclopedia
What's wrong about the name? Again, perfect name (he is a nearly unstoppable force if played correctly), very original, absolutely no problem... Again, Blade Master sounds too generic, pls keep the cool, imaginative and unique names
Morphling: I think I explained often enough why his current title is awesome and fits perfectly fine at these links, no need to do it again.
PotM: Not bad, but current one is okay as well. She's just called PotM all the time and this would destroy the reason for this, so it's more classic.
Zeus: I explained already as well why I prefer the name Zeus (it's just too classic Imo). The title depends on the name you choose.
Furion: Forest Guardian sounds lame. Archdruid would be awesome, TUp for that.
Lina: Anime reference. And the Pyromancer doesn't fit to her ultimate. Slayer is a perfect name looking at her combo with the ultimate, although I don't like it that much. If there are better suggestions, I could agree to changing this name.
Davion: I still prefer Sir Davion over just Davion. It's more unique, absolutely fitting and sounds cooler. http://www.playdota.com/forums/29750...change-davion/
Huskar: Current name fits, but I personally don't really like it. This new name sounds even less cool and more generic though, so for me it's even worse. He's a lot more than just a berserker...
Leviathan: Current title sounds cooler.
Gondar: Bounty Hunter sounds cooler and more fitting Imo.
aar: Why? I see no need.
Techies: Hell freaking no. Why the fuck would you ruin one of the best names in dota?!?
Visage: Visage is one of the coolest names Imo. I don't get the current title, so I'm not sure, but I like your suggestion partially. Sounds cool, but I'm not sure if it's that fitting.
Dazzle: Dazzle is an awesome name, though slightly ironic as he's a Shadow Priest, so he can't really dazzle someone. However with his mask, his staff and his skills he can still be dazzling xD TLDR, I really like his name. Your argumentation is like saying a hero shouldn't be named Ben because that's too similar to Sven. It makes no sense at all and isn't a good reason. Shadow Priest is also pretty much okay.
Leshrac: Oh pls, stop ruining the coolest and most creative names in dota.
Abba: Wikipedia can be very informative. I think it fits perfectly.
Lycanthrope: It's called Lycanthropy, so Lycanthrope fits a lot better than simply Lycan Imo.
Leoric: Hell freaking no. Wtf is this shit seriously... Epic classic perfectly fitting name - he has even a crown on his head - what do you want more?!? Hellrazer just sounds worse and doesn't fit that much.
Broodmother: Broodmother is a perfect, fitting, creative and cool title, so pls keep that. Name could be changed, but I'm not sure into what. Tsuchigumo sounds kind of unfitting for a spider in wc3 Imo.
Eredar: I'd go for Gnoll Torturer suggestion: http://www.playdota.com/forums/27800...noll-torturer/