It's not just wake vortex. I recall watching a trainee vectoring a KLM CityHopper onto the ILS behind one of the based 737s. It was normally an F100 (or maybe a 28) but on that day it was an SF34 - nothing to indicate the aircraft change.
Trainee duly put the thing on the ILS and threw it to TWR and then, with nothing else happening, he turned to me looking pleased with himself for his neat vectoring and we talked for a short while before I had a quick look at the radar. KLM had rapidly caught up with the 737 and was way closer than I had any right to let it get. Lots of quick talking to TWR - reduce speed to min safe approach and stuff like that - and it all worked out OK in the end, albeit very tight on the runway.
T'was many years ago. It only happened once (that I'm aware of). TCAS not installed widely at the time. We didn't have to pack 'em together routinely. No little radar in front of TWR at the time (I think it was in the process of being replaced at the time). Weather not very nice. But it shook me up. Lots of holes in the cheese started to line up and it shook me up some.
Does that warrant clogging up the RTF with mentions of the aircraft type? My own view - I'm inclined to say yes. Given the number of times I've seen aircraft that didn't match the filed type appear out of the murk over the THR and the number of experiences related in this thread, I'd say yes, without a doubt it's worth the minimal increase in RTF loading.