I think it will just look a bit daft to be honest. I've always liked that test cricket hasn't had no's and names on shirts, as i've always liked Rugby just having no's and no names at international level. I mostly think it just looks better. I cringe a bit at names and numbers being on first class teams shirts.
I'd also say that being able to identify players isn't an issue. The scoreboard and announcers keep you abreast of who is bowling and batting, and id say the field settings are far more important than who is in each position.
I'd also say if the ECB wanted to help promote test cricket, then a commitment to 2 tests a summer on terrestial tv would be a much better start.