Tl;dr - yes but games currently make wet weather driving far more difficult than it really is.
Yes, we need wet weather and it seems the time for decent implementation has come. In the UK rain often has to be considered a factor so it should be in the game.
From many years real track experience in all sorts of cars my opinion is that racing games currently make driving in the rain far more difficult than it really is. I've had some superb fun battling a Caterham around Anglesey in the rain and crosswinds high enough to move the car right to left across the track, sure the semi slicks are tricky when cold but once they warm up they allow easy to recover slides and the fact the tyres still squeal in the rain surprises many people. Cars like the Honda S2000 were made out to be some sort of death trap in the rain but they have plenty of grip and could easily keep up with FWD cars with similar power. Take the right car on a wet track day and it can be awesome fun, my Audi RS3 running on Michelin Pilot Super Sport tyres was as easy to drive on a streaming wet airfield though big standing puddles as it was in the dry. Unlike games, the stewards won't let you out on a wet track on full slicks in the rain!
At rally school, they deliberately wet the track to make learning the skills easier and eventually add an extra challenge, this has to be part of a game for me. The Porsche Driving Experience with the Kick Plate and Ice Hill are both superb ways to learn more about driving in the wet and with low grip. Take a GT3RS on Pilot Cup Sport 2 tyres and prepare to be amazed how much grip and control a fast 500bhp RWD car really has, oh and I'm afraid it always understeers before it oversteers though many sim racers like to argue this point (AC really is very close to the real GT3RS in the dry imo). In games like Forza cars like the GT3 RS become almost undrivable in the rain and it simply isn't the case.
If games could more closely match real world wet track driving then it really would be great.
So back to the games:
--- Forza 6 fixed rain and standing puddles (some on hills!) was awful and the AI still follow the dry lines with race ruining consequences.
+/- Pcars was ok, especially for a shortened Le Mans 24hr race with day, night, early morning mist and rain. The AI seemingly being unaffected by the rain was disappointing and the press demo of pcars2 seems to be exactly the same.
+ I'm hoping Forza 7 and pcars2 have moved this on with the true dynamic weather they claim.
++ DiRT 4, I like it and I know many others don't, had superb weather effects, stages wet after rain could be more tricky than stages with full on rain. Rain and fog at night on long stages are intense and eye straining. I don't know exactly why but I really click with the cars on snow stages. Maybe they make a bit too much use of weather to create artificial difficulty but other than that, brilliant.
+++ F1 2017, so far for me F1 2017 does the best job of simulating changing track conditions. Damp tracks are treacherous and lap times increase quickly as the rain starts to fall. The drying track and drying line are brilliant, makes a real cat and mouse game of when to change tyres.
+++ Motorsport Manager deserves a mention too because wet weather really adds a huge amount to the race strategy in this little game. Try the Bottom to the Top Challenge (not career) if you want to see this for yourself.
FIFA 17 deserves a mention here too because the wet pitch and ball really do change the game so well. Through balls skid on way too far, passes go astray and strikers skew easy chances. Wet weather can be made both fun and realistic in games so I hope we see that in the racing games this autumn.