@Pauljc comparing wolves to vanilla is a little off, especially the pod route as vanilla termies don't get the option.
2 chainfists are good, as you say a spare can be useful. No more than 2 though, you'll never really need them.
Cyclones and assault cannons both have uses, imo. Heavy flamers are either superb or weak, depending on the opponent. Against any infantry with a 4+ or lower they really rock. Against infantry with a 3+ or better, they pretty much suck. 1 shot before combat and no overwatch due to relentless will not beat the other options in that situation, and against hordes you'll likely be deploying further back anyway, giving the cyclone the advantage with its shot options. Underestimating flamers isn't my weakness, but as a reverse of Pauljc's sentiment, many people swear too blindly on them.
Not going to question the sanity in dropping a 5 man terminator unit with 2 charas in there into the heart of the enemy...
Terminator librarian's are the only way marines have atm to make a libby tough, and they contribute more than any other non named chara unless your captain is making your bikes scoring. In other words, keep him.
As to your original question. You do need to be aggressive, but tactical terminators are good for their balance. You need to play them by ear and situation. Deep striking into a guard line is a good plan, but into a nid line you're throwing your unit away. Deploying normally against orcs is a good idea, it adds more shooting to your army. Against dark eldar it leaves them stuck footslogging to get into the thick of it, while your opponent shoots the hell out of them. Etc~
Basically, if its gonna kill you close up, don't get close, but if its gonna shoot you, get in its face asap.