If you want to house rule some uber unfluffy wrecking-ball unit that doesn't fit who the Salamanders are, then obviously do it at home. Anything beyond house rules will need to stay within the realms of what the rules allow.
Seriously, you're getting hung up over these drake scale cloaks now, which have no reason to be able to do anything, and your insistence that they should is getting in the way of just having cool-looking models. Cool-looking models are literally all you need to distinguish your guys from the next player's. By all means give a Sternguard unit badass cloaks, but just leave the pointless magical boost effects at the door. Like I said earlier, it's just an excuse for not using them intelligently, or even well.