what about implanting a rule which would prevent a player attacking someone much smaller ? (to attack the level difference must be less than 5 and no more than 50% power difference). Exception for inactive players (or players without an alliance), which could be attacked by everybody.

I think they fixed that in the current post... Oh, wait...
They fixed it sothat a commander from your alliance sending backup troops have them acting at your level.
Now, the big boys can just steamroll the smaller players, and, the "join an alliance for protection"... just doesn't work.
"spend more money"... yah, 10K USD?  no.

units hit... gets filtered (SHIT being read)
ANY word that contains any of the banned words, or any phrases containing them. 
The whole word-filtering thing is seen as an on-server joke.