I like riding in the rain. I think it's fun. And I've learned that it washes off.

Having fenders vastly improves things. When I get caught in the rain on my fenderless bikes I notice that 80% of getting wet comes from the water kicked up from the wheels. And unlike the water that is falling from the sky, the water off the wheels contains mud, rocks and sand that turn me and the bike into a mess. I arrive a lot less soaked and a lot cleaner if I have fenders.

It's rare that the rain is coming down so hard that if affects my vision. I just wear my usual sunglasses, or if it's darker out my clear safety glasses. Occasionally I'll wipe them off on my shirt when I stop. There have been a few times where it's rained hard enough where it was easier to see if I just removed the glasses altogether. In those situations I wind up riding a little slower anyway.

Never had a problem with my hands sliding off my grips. On my rain bike I'm just running the stock rubber grips, so they're nothing special. Do your hands slide off when they get sweaty too? May want to change grip material.

Haven't had any trouble with traction. My main rainy-day bike runs 32mm tires, so not super thin but not extremely wide either. After I read Sheldon Brown's analysis that physics won't allow bicycle tires to hydroplane until somewere north of 100 miles per hour I gained a lot more confidence in my tires staying planted on wet pavement. Manhole covers and railroad tracks are another story; avoid them in the rain.

I normally carry all my stuff in re-usable cloth grocery bags which I then place in my panniers. That makes it easy to carry everything too/from the bike. My panniers are rain resistant, but not waterproof. When it's really coming down hard I'll wrap those grocery bags in plastic grocery bags which keeps all my clothes nice and dry.

As far as motivation I always tell people that when it comes to bike commuting, "Deciding to do it is harder than actually doing it." Whatever the weather obstacle, be it rain, cold, ice, snow or extreme heat, I can easily come up with excuses not to ride when I'm looking out the window. But once I'm a mile down the road I always think, "Hmmph. This is no big deal!"