Think of 2.2 as version 3 of DSL. The 2 versions are incompatible with each other (I think 2.1 bots work in 2.2 but their batteries work differently) and they have different metagames.
They both use dsl-s building style, but 2.1 is more focused on spamming weapons like razor tips and beater bars, whereas in 2.2 replica weapons like frenzy hammers ans mechavore discs are overpowered.
2.1 is basically dead at this point, so I would say don't bother with it. If you're not a fan of 2.2's imbalance, the Ironforge mod is a good replacement. Hopefully this covers everything.