I'd say go for it. The wye is a great river to fish, i think the point Tim was making is that people can end up going rather underprepared... I certainly cant imagine what would happen if i ever took on the wye with the feeder gear I use on the thames. I doubt if i'd ever retrieve either fish or terminal tackle on a single cast! But i suspect the severn can probably throw all that at you too.
On even my best wye sessions, i've usually lost a fair number of feeders - funny how the best pegs are often the ones that eat tackle. That's ok, i make my own now, so i'm not throwing away £2.50 every time i cast.
The only other issue with the WUF beats is that the prebooking means you'll often be committing yourself to fishing well before you know what the conditions will be like, and like Geoff says the EA level guides are an excellent resource for finding out what the river is doing (and importanly, what it's been doing over the weeks before your visit). Based on that, you can make some decisions on what to take with you, if it's lower than normal then I will generally do a bit of trotting during the middle of the day.... however, you may be lucky and catch it when it's just dropping nicely from some higher water, in which case a normal groundbait feeder approach will work all day.
Last year on the 16th, that's exactly what the wye was doing, it had been quite high right at the start of June and had dropped a bit for the start of the season but still had more colour than you might have expected, the chub in the river were absolutely suicidal and this created a problem I've never encountered before, how do I keep a bait in the water long enough for a barbel to find it without it being grabbed by a chub?! I never managed to work the problem out, but I did catch nearly twenty chub between 2 and 4 pounds trying!
