Why compete with small agile ship ?well ok, it's maybe not exactly awful, but here is the thing, a tank cutter is not going to be able to keep that boost up if he wants to tank. he can do maybe 2 boosts and then its back to crawl speed again.
attacking ships like for example the FDL or the FAS with their cruise speeds of 300+ and boost speeds btw 500-600 is not going to have any problems keeping up as they can keep 4 pips to engines at all times unless the cutter decides to fight back.
It is however possible to match the speed of assault ships with a cutter if he builds for that. and flying a lightweight modded cutter packed with PD's is probably the safest thing someone can fly in this game.
but flying a tank with the intention of running is just a contradiction and never a good idea.
A big heavy ship will never be as agile as a small ship... And considering how cutter is really bad at turning itself... It should defenetly not try to compete with agile small ship.
In the other hand shield and hull tanking is a good idea for battleship. And like someone wrote somewhere, big three ships are meant as support ship not as godlike ships killer.