Honestly I completely agree with you, I feel that there does need to be more 1.8 gamemodes. Unfortunately you are talking to the wrong people to try and get this suggestion to take off. I feel that 1.8 has so much potential but as I have said in other threads, the only thing holding it back is the fact that there are only 2 very similar gamemode on the 1.8 servers.
I've realised that this suggestion isn't really down to what people say on these forums because what the members on this forums want is more for 1.9 considering cube does have a bigger 1.9 community. It's the general minecraft community this will effect essentially considering if you want to grow the 1.8 side, you are looking to attract players who aren't consistently playing on the server yet.
All I'm going to say is if you are saying "Players just need to give 1.9 a chance and the might enjoy it" that is completely the wrong mind set. If minecraft players haven't tried 1.9 pvp yet they must have been living under a rock, its been out for almost 2 years. There are a lot of players who just don't like 1.9 pvp full stop and by getting rid of 1.8 all together you are ignoring almost half of the minecraft community.