Well if this photograph of the back of the Stormraven box is real then the Blood Angels are not the only Space Marines that can use the Stormraven.
As you can see the box has a Grey Knights painted version with lascannons.
Now to be honest I have never been one to follow GW’s doctrine to the letter, if I like a model and want to use it in a particular way then I will (and usually I will ask my opponent’s permission too). If you like the model, I would say buy it and paint it in the colour of your chapter (or legion). Yes it may be “problematic” if you wanted to use it in a tournament, but for me gaming it about gaming and not competitions. Just because a rulebook says that I can’t use a model, doesn’t mean that I can’t use that model. The Warhammer 40K universe is very big and despite the Inquisition, I am sure that in some depths of the universe there are Space Marine chapters and Imperial Guard units using stuff that according to doctrine they shouldn’t. Where needs must and all that.
Actually if you go far enough back in time you can find in old copies of White Dwarf Imperial Guard units using Land Speeders and Rhinos – that was in the days when GW made very few plastic kits and there was no Forge World. So it made sense for all the forces of the Imperium to use the scarce plastic kits available. Alas today where we are awash with plastic kits, GW can now make kits for single chapters that “can’t” be used by others.
So, if you want to use the Stormraven for your Imperial Guard or your chapter of Space Marines, then go ahead and do so. You’re not going to kill the fluff if you do.
Thinking though that one of these Stormravens would make a nice Inquisitorial transport for my Inquisitor – and we know that they would have access to them…