The Melta rule in this edition is odd. A melta weapon according to the lore should be a short range anti-tank weapon, but instead what we have is a short range weapon that's good at killing Terminators and pretty much nothing else.
For example, a standard Melta in short range against a Chimera (T9) will wound on a 4+ but against a Manticore (T10) or a Leman Russ (T11) will only wound on a 5+.
If we switch the rule so that Melta X increases Strength instead of Damage then with your standard Meltagun (12" Str 9 Melta 2) when you're within 6" (which is pretty short range) you're wounding T9 on a 3+, T10 on a 3+ and T11 on a 4+.
It's a pretty small change for 11th but one I think would fix t