Well, it’s not worded in a very good way. If it was meant as constructive feedback, the person really needs to work on their ability to convey that better.
I think there are merits to priming the entire thing once’s it’s fully assembled. It would help give everything a uniformed look (which I think is what FB guy was trying to say) and it could fill in the small gaps around the legs. I’m just nit-picking and I don’t think your average laymen would really notice the gaps once the project is finished. You could also fill them with epoxy sculpt like green stuff and just paint the seem to blend in.
if you did prime the whole thing, I shiver at the thought of having to cover that GIANT sauropod in paint.... that’s a LOT of extra time, effort, and expensive paint to something that is not totally necessary.
my advise is to keep doing what your doing and figure out the priming situation later. Maybe put a hold on painting things until the entire thing is assembled. Then you can decide if you want to prime the whole thing or just paint the individual parts.
I hope this helps! It’s just my opinion and I love this project! The fact is you have an awesome model, great imagination, and it’s gonna look incredible once’s it’s done! I hope GW sees your hard work and are inspired to do something similar for a future release. Keep up the good work!