Put them in bigger suits.
On a serious note, I think that Fusions and Missile Pods are probably the way you want to go - you don't *need* that much AP2, and a Riptide with Ion Accelerator should cover you on that - for everything else, just pushing through weight of wounds will do the job admirably. Remember that time I charged a full 5-man squad of Assault Terminators into Fire Warriors and they all died on Overwatch? I think there were two Crisis Suits with Plasma Rifles and they killed one Terminator. All the others died to Pulse Rifles and Missile Pods. Missiles with Buffmander (Commander with Iridium, Puretide, Multispectrum and CNC Node) are like Broadsides that can JSJ back into cover to make up for the decrease in resilience. Missiles are long-ranged enough that you can stay out of range of most small arms or charged, which I see all the time when people load up on short-range loadouts for Crisis Suits (remember you're two 14pt Space Marines strapped together but costing half as much again or more; Crisis are fragile and you don't really want to get any closer than 24" because your average JSJ of 7" will only *just* put you out of small arms range), have good damage output against a wide variety of targets, and benefit the most from Buffmander. Throw in a couple of Shield Drones to stop Lascannons and Missile Launchers just annihilating you, but try and keep the points cost of the unit down as much as possible. As said, they'll die to a stiff breeze no matter what 50mm bases tell you.