This is actually how WCS was when it started (as wc3 mod) on 1.5/1.6. There were only the original 4 races though. Human, night elf, orc, and undead. It wasn't until later when servers started adding their own customization and started "saving xp" that all these new races started popping up. It was called superhero mod back then too.

Anyway, point is, this could work and has worked in the past it'd still require a reset to make things interesting again for the older players who are just bored of the mod in general, but let's be honest. CS:S is dying. Zero make a CS:GO WCS mod and start from scratch. It'll be fun for everyone again, including you!