Honestly, you are speaking to the overplanners club. The folks who post here are largely big time planners.
I've done bounceback offers for free dining- so I guess that makes me soemoen who planned a year in advance- but really I just picked a resort and sat on that choice for nearly six months. (BAck then, dinign reservations started at 180 days)
I've also done a few last minute trips. I refuse to pay top dollar for airfare, so I booked about a month in advance.
You don't HAVE to pick much of anything in advance. I like to pick a resort, get cheap airfare, a deal on my rental car(If I'll have one). Beyond that, I like to pick a park for each day, and no more than one dining reservation per day - usually not quite one per day - unless I'm on the
DDP. BUt equally, you can eat all quick service dining - and pick all your dining onthe fly.
The new DIsney dining reservation system is kind of cool because you can actually see the current menus for most TS places now. The downside is that I bet they are now semi-locked in 90 days out, and the competition for dining choices is much higher at 90 days than it was at 180 days.
I more or less pick my park by either going to the EMH parks or avoiding them. If you are avoiding them, then you can pick almost any park each day. You may want to go to HS ona Fantasmic day, or you may want to avoid that as well for lower crowds all day. If you can call up the park hours for the days you'll be there, that may well help. Otherwise, you really can't go wrong.If you happen to pick MK on a day it closes early - then that gives you an evening break, and you'll get lower crowds. If you go on a more extended hour day, crowds will be higher, but you'll get more time. It pretty much evens out.
This past March, I put together a great trip about 45 days in advance. We changed some of the dining while we were there even! Everyone said it was one of our best trips ever! Mostly because I used strategy, not strict planning per say. When my family wanted different dining, I knew what the area options would be, and I knew how to get new ones; at the resort concierge desk, as it happens. Making it happen was easy, and
I didn't get flustered or resentful that they wanted to make a change!
In my opinion, anything more agressive than what I ascribed is TOO much. There's no point in making a strict plan of your dining a year in advance. The only thing to do more than a year out is dream and save your money, unless maybe you are planning a big wedding or something equally major..
So relax. You won't see EVERYTHING on any trip, no matter how much you plan. I've also been enough times to know that something unexpected happens nearly every visit: an injury, and illness, a problem back home. Stuff happens and you can't let it ruin your trip. I worry about some of the folks who try to plan every detail a year in advance before hours are even posted. I worry about those who have the fatasmic package, the boutique for their daughter, two TS meals per day, and a specific ride order with specific times - are these the folks I've seen yelling at their kids who want to go on Peter Pan instead of the planned Dumbo? Are these the folks who post after their trip how a certain restaurant didn't live up to the hype?
there is some advantage though if you know what dining you want at the 90 day mark. Otherwise, just browse and pick from what's available. Sometimes the most fun places are the ones we didn't expect to like. One place we first tried last year my whole family loved! I had intentionally avoided it for over ten years!
I start the planning for DDP ressies next...I have actually started looking at that already, have to wait 90 days out to book dining...so I will be ready for August 3rd! We are so excited to go back to WDW!...Usually, I am planning at least a half a year out!
We only get to go to WDW every 2-3 years so as soon as we decide on a date, I start planning. For our past trip in Dec 2008 I started planning 18 months out and this way we made payment every month on the trip and everything was paid before we left. 
