There are many Tactics Server and Tactics is important. But to my very surprise: In my games are moves without tactics too
I would like to have "Non Tactical Problems" , maybe problems with about equal material where the goal is to find the best move. I think something like the software "Chess Hero" would be wonderful: It can present a (random) position of a database of master-Games and asks for the best move. The user gets a punishment according to the evaluation of his move by an engine and the evaluation of the "best" possible move. I think a small modification would help to implement it at a server. The server has/knows PV1,PV2 and PV3. If the user choses the move PV1 he scores 100%, less if he choses moves PV2 or even PV3 and he scores 0 elsewise.