Oh, didn't see this til now
A: current beam rules
B: 1-3=0 hits, 4=1 hit, 5=2 hits, 6=3 hits. No rerolls.
C: 1-3=0 hits with a reroll, 4-5=1 hit, 6=2 hits
D: 1-3=0 hits, 4-6=1 hit plus 2 more ADs hitting on 4+
E: 1-2=0 hits, 3-5=1 hit, 6=3 hits. No rerolls.
Note: all of these mechanisms maintain the average hits of 1, so no rebalancing is needed
A has a high chance of getting 12+ hits, and high chance of a low number too.
B and D are virtually identical!
C is very restrictive. You are very unlikely to get less than 3 or more than 9 hits.
I think E is my favourite. You are unlikely to get less than 2 or more than 10, but the potential is still there to get 12+, once in every 150 rolls or so.