I started using Ronin more regularly, it's a lot of fun, but quite hard to get close to opponents without losing too much health. I'm hesitating between giving him an additional boost, or nuclear ejection. Both can be useful...
His sword slashes are sometimes a bit cheap, killing pilots when they're inside a building. But I like it that way.
I'm not sure how to use his phase shift ability. It seems too short to be usable to move very far, should I always use a dash when entering phased world ?
Use phase to get behind enemies. For example if 2 enemy titans are facing your titans firing back and forth you can just rush in and phase behind them and shotgun from the back. Now they have to focus on you and your team can hit em when their back is turned.
Ronin is a very disposable mech when it's mech vs mech since in his optimal range you will always be taking dmg. That's why I always run nuclear eject. For his ability I would recommend the double electric charge attack. You always need to hit the enemy with that before you rush in and nuclear eject.