They can't afford for Roman to fail.
In the corporate world of wrestling the marketing pushes are planned months in advance.
Where I work the only WWE toy on display with all the "must have" christmas toys in the busiest walkway of the store is the Roman Reigns create a wrestler one, I don't think we have much of any other WWE merch other than the video games and 1 John Cena t shirt in a childs size.
They probably have a shit ton of different things made/printed with Romans likeness plastered all over them ready for wrestlemania as well.
The noise the crowd is making doesn't really matter to a behemoth the size of WWE as much as shifting low to produce high profit margin toys and tshirts.
I mean has the "divisive crowd" ever affected Cenas ability to shift merch? quite the opposite, Cena has been the cash cow for years despite being booed out of some arenas, all you have to do is go to a house show (even one he's not on) and see how many kids in Cena shirts are there to make you realise why they pushed him so much and what they are attempting to do with Roman.
I don't even think Roman is a bad choice for that role. He's not an amazing wrestler or any thing, but he's young, charismatic, has a good set of genes and the ladies seem to think he's hot.