An idea is to keep the invisibility, but reduce the sword to a stone sword and reduce the time you're invisible.Blockwars would definitely be nice for bedrock but I dont think it should be implemented the same way. For example, I think that ninja should NOT have invisibility due to combat mechanics making it far too strong already. The invisibility will just make new players that dont know about it not want to play it at all as it just looks like hacking.
I'd so say that only CTF should be implemented because core is boring and imbalanced.
If you look at the playercounts, games with large teams do really well with 4v4s being the most popular on eggwars and skywars so the 8v8 fits the playerbase extremely well.