In my experience. it's always easiest to go with the trait you have the most dice in. Ronan has 2 ranged and 1 melee, so in general I would never even consider going melee with him, early game or otherwise.
This is where it becomes important to coordinate with your fellow heroes to make sure you build a decent hero party. If I'm looking at Ronan as my hero, I'm not looking to fill the role of melee tank. Let someone else take that role, and Ronan can look into being a ranger. Possibly a runner with that Swift skill boosting your speed.
Hmmm note that we already have Ispher for ranged purposes..he also has lower armor than Ronan meaning he cannot enter melee with peace of mind..the wizard role is upon Jaes(he's going to buy immolation because of his skills)and tank upon Onefist(sword only).So i don't see the point of losing damage potential as a party(that means the monsters have a better chance to stay on the board for more rounds-this is a bad situation)just for one extra black die on his ranged trait.2 black dice added to the dmg of an axe is an overkill nearly always.Besides crossbow is more expensive and the blue die sucks(it's the worst basic die)..
ps.from my point of view it's not mandatory to stick with the highest trait always..these 'hybrid' heroes(with split traits)are built this way to show us different options