Well… More weapons than in ET:QW, and it was fine. About maps - yes, plenty “community”-made maps did the job that developer did not. therefore, i see no argument in ET few preinstalled maps, as it practically had thousands of maps. Does not matter who made it all.
About unlocks - what they do is putting some penalty on class-change, doing that they deepens the gameplay experience in terms of tactics. The longer you play certain class, the higher the cost of a change, so best approach is choosing right class from the beginning. It fails a bit when campaign is considered though, because player may have no idea about what the next map objectives are. If the campaign would be made up of consequent actions, also using using some previous map feedback to make things from the “past” matters…
About symmetry - there is no, as the sides of the map are not mirror-copied. Solely because of that same classes produces asymmetric game. If example is needed - say a good sniper spot… Better bottlenecks…
About damage model and duelling - agree, it would be nice to see the same as in ET, with the same good old headshot sound :).