I'm very much considering removing them, but I'd like feedback on the topic.
I've been told that cluster alliances generally don't happen (apart from the standard cluster-wide NAP at the beginning of the round that falls apart). Top galaxies use this to use the other galaxies as farms and the other galaxies feel unable to respond*, and this isn't offset by the ETA gains.
Therefore, it either restricts you from 5% of the universe (9 galaxies or so) or causes you to be farmed. It also complicates any sort of defence rules about out of galaxy defence, and contributes to support planets.
I'd like to hear if this is a general feeling or if a minority has spoken out, thanks
*Bashar would be the first to point out that the other galaxies could and should get together and retal back, using the cluster ETA to their advantage