Add timer back in, set it to 10mins instead of 5-7mins.
Take out cc and hive healing.
Timer forces a more aggressive game since people have a desire to win they will go at it a lot harder.
I'm sure joining a late game as an un-skilled players versing level 10+ people is not much fun at all.
People just group up around the CC and Hive now healing it.
Games are pushing 40 - 60mins.
Games shouldn't go much longer then the first couple of people getting to level 10, when every one is near or level 10 it sort of takes the rewards of all your hard work to get the upper hand away.
Many more points you could focus on y the 2 changes should be made, leave that for other people to add
O yea, skulk base amor of 15 instead of 10 would make the start for marines just that bit harder to get the early advantage.