I wouldnt take hammers for GKSS or GKIS. First they cost pts and second you get them on paladins and terminators for free which i think a list may need. Second razor back are nice but 45+ pts is pts that can go towards trps. In my opinion you dont need razor back for trps who can deep strike via 1dg using a servo skull. also you can split those guys into combat squads and DS them in two different areas. 0 pts for st5 sounds cool but again it is pts you need to your army. Dreads can spend 5pts on st8 autocannons.
terminators should be only 205. whats the combo i would go with 5man with halbred & incinerator DS on the field as well. maybe one DM for justicar. The reason for this is that they are shock trps. you dont want anyone paying attention to them. I would get a 5 man squad of paladins with 2 psycannons & halbred with a hammer if you want but i like going first with st5 weapons and WS 5. psybolts dont go towards pyscannons FYI.
In a list of 2000 pt competitive you can add some purifiers but you will have to take away a dreadnaught then again since u dont have no 2nd hq u could fit a 5 man unit in w halbred and 2 psycannons. This is just my opinion. GK must be played like an orchestra. each unit and attribute being used correctly. Dont forget about the GM abilities with up to d3 units.