just to remember...roamers are heroes that won't stay in a fix lane, it means that they will do rune control or will be jungling during the early/ mid game phase.
ofc that a ganker suits it better cuz of their capacity...
1st skill can be buffed a bit. increase it's duration by 0.5 sec, maintain a 1 sec fade time.
2nd seems fine for me, but the mana cost :/
3rd skill is ok
ult is fine somehow