In retrospect there is a way the original 5v5 magma chamber concept could have worked...

Random map.

A phrase long time RTS players might recognize. (looking at you ghostcrawler)

While the concept would not be a completely 100% randomly generated map based on a style like "black forest", "Arabia", "Mediterranean" or "Oasis" Make it so that one of several different maps will be picked could have been a way to have made the original 5v5 magma chamber work better then dominion (R.I.P.).

In some way this would challenge players in a greater level expectantly junglers. Different buffs on different maps. Even things like different durability of turrets could make maps more ideal or less idea for a team comp. Heck this would even mean that a mess up on one map making one buff too strong would only effect one out of every 3 or 4 games.

Have it all tied into the same ranked system so people do not feel one map is more important then the others.

Just one could have that was never really explored.