1. I don't think existing ships should be remodelled this way at all.
2. I do see some potential for ships in this kind of style as new ships. With all the wars, each house developing specialized atmospheric fighters (still space-capable of course) for those times when they need more precision than orbital bombardment makes perfect sense to me. Not many models, but some - maybe one per house and a few other relevant factions, at least one civilian type since it has non-military applications (particularly for the IMG, to support planetary surveys)...
The fact that it wouldn't actually work is irrelevant next to the fact that it looks more suitable for it and we can say "Valhalla did it." if anyone asks.
So yeah. No to replacing old ones, yes to making new ones like this.
Plus, it'd work for people like Beagle that like this style.
