It can move 36", sure, but if you've got guys in trukks, guys on bikes, guys in the Stompa, the Stompa itself, etc. it runs out of safe places to go pretty quick. Also, the Titan Holofield is vs hits, not glances/pens. I just don't think it's quite as dire as you're making it out to be. I'm not saying you "picked it on purpose" to complain or whatever, people play what they play, but older books will have trouble against newer things. I played the 3rd ed Necron codex all through 5th edition, I know all about it.
How are stick bombs or some of the weird ork guns? I don't know the book super well, but I know it's got a bunch of answers (a nob with a power klaw and a bunch of boys will keep it locked up for a while) and it definitely wasn't designed with 6th in mind. I'm sure when they get a new book, they'll have even more answers.