I have only played as a Titan and do not feel disadvantaged. My advice would be to change your playstyle if you are getting wrecked constantly. That usually happens as a result of rushing into situations that are not winnable. Use the radar, avoid areas that show multiple pings if you are lone wolfing. While the titan can run and gun with melee and shotguns, that is not always a viable way to play. On some maps yes, on others no, so learn where it works and where it doesn't. Other than that change your gun. If you play auto rifle/shotty, switch to totally different weapons. Try the new and improved scout rifles, they will force you to hang back a bit and play with a more considered style. If you want a total change then try playing predominantly with a sniper. It will force you to learn different map lines, cover points, map control points and so on.