So lets look at your points:

1. If you are changing to SPG because Marriott increases their category levels, I'm afraid your going to be very disappointed. All the hotel chains do that. Now, each year, one chain may have more increases than another chain, but usually over a couple of years period, they all tend to average about the same.
   
2. Rate Increases (weekends) - I've found that in general, Marriott prices tend to be lower than Starwood. Sure you may have an exception here and there, but overall, Marriott's just tend to be less expensive on the whole. (Note that given your specific travel destinations, you can check and see if that holds for you or not.)
   
3. Lack of Promotions - Starwood hasn't really put out much in the way of promotions over the last few years either. So I wouldn't jump ship expecting to be "wowed" with better promos.
   
4. Hike in Award rates - See #1 above.
   
5. Lower availability - This is definitely one area that SPG does better than Marriott. But even then, I have usually been able to find award availability with Marriott given they have many hotels in most Metro areas.
   
6. Mixing Restricted/Pre-paid rates - I'm not sure I understand this one. Specific hotels may offer pre-paid or 'restricted' rates, but the T&Cs stating that have always been very clear. And SPG hotels do the same thing. I was just looking yesterday to book some nights at the one and only Starwood hotel anywhere near the panhandle of Florida. And guess what the cheapest two rates that come up are? Yep, pre-paid.
   
7. Hike in GC awards - Definitely, Marriott has decided that their previous ratios were way out of line. (And given the number of posts on FT about how awesome they were, Marriott probably was right.) But I'm not seeing that SPG has a better GC award offering.
   
8. 4PM Checkout - This is definitely a nice SPG benefit, but once in a while it can be a pain as some hotels think they are Conf. Ctr or Resort hotels and thus don't have to abide by it (even though Starwood doesn't recognize them as such.)
   
9. Upgrades can be nice, if you can get them. You might want to check out the http://www.flyertalk.com/forum/starw...um-status.html thread. I tend to agree with most of the comments in that thread stating that upgrades really are very dependent on the specific hotels you visit. In 5 years as a SPG Plat, the only hotel that consistently gave me an upgrade was the King Edwards in Toronto. (And unfortuantely it is no longer a Starwood hotel.) The Westin there and the Sheraton at the airport have never upgraded me, ever (I've had about 10 or so stays across both of those hotels.)
   
10. 24-hr check-in - That definitely sounds like a nice benefit (but I don't think an "entry level" Plat gets that. You have to be a 75 night Plat for that benefit. So you won't get that benefit for awhile. Also, I know a number of Marriott hotels on the West Coast are very accomodating to early arriving travellers. So if you tend to stay at the same hotels a lot, I'd think both Marriott's and Starwood's hotels would probably be willing to work you into a room much earlier than normal (or stay later than normal.)
    
11. AAA Rates - Marriott has those as well as other rates. And as stated earlier, at least for most of the areas I travel, Starwood hotels tend to cost more than the Marriott clost to it. For example, I've been traveling to Overland Park, KS recently. There is a very nice Sheraton and a nice FS Marriott there. The Sheraton costs about $40 or more per night. There is an Aloft as well, but it costs the same price as the FS Marriott does (and at least the FS Marriott has a Starbucks in its lobby. )
    
12. Status Match - Yes, SPG will give you a one-time only match to Plat assuming you have never been a Plat before with SPG. Note that I suspect they will only offer you "entry level" Plat, not double Plat (75 night) or triple Plat (100 night) status. So you will still have to stay 75 or 100 nights before you would get benefits of those higher status levels.

With all of this said, I still like Starwood hotels and do stay enough to keep Gold level with them now. I dropped this year after 5 as a Plat due to the limited benefits and the higher costs of their hotels. But personally, if you are jumping ship just because you are angry with Marriott's "devaluation", I'd suggest you stop, take a deep breath and then look objectively at what you really like in each program and what you want out of each program. Then look at what you can earn in each program. After that, make your decision objectively.