I main a Titan but goofed around on the ole lock for a little. I found running the solar wind solar flare grenade gift of the sun build works well for zoning. Especially for a more passive play style. You just slap enemies away and then block the way with a sun. Also with a fireteam if you use song of the flame or whatever it's called you guys can wreck house. The nades boosted on a armamentarium lightning grenade Titan is truly scary