I expect "Free to play" to become "Free to play, but every server not run by Valve automatically boots you." very rapidly. There will likely be server mods that boot anyone with less then 500 backpack slots before the week is out.
Beyond that, meh. All these new items, and not one thing to screw over sticky spammers.
Valve doesn't run any servers, so that would be impossible. And any backpack slot thing would be set to 300, since that's the starting value for the "paid" people (you have to purchase expanders to increase it 100 at a time, up to a max of 1000).
As for stickies, cry some moar.

i feel another "free to play, pay to win" coming on. can't blame them really. these systems make assloads of cash because morons or kids with access to mommy's credit card will shell out hundreds for better weapons in a video game.
...unless all the bought stuff is purely cosmetic, in which case i'll start chewing on my work boots.
With a few exceptions, you can buy pretty much any droppable item in the Mann Co. Store, along with a few store-exclusive items. However, anything store-exclusive is purely cosmetic. More importantly, the current system of a certain number of random item drops per week, coupled with rare hat drops, won't be changing. From the time the Mann Co. Store was launched, Valve was adamant that any items affecting actual gameplay would be freely-obtainable, and they've restated that today. There really isn't any point to buying weapons from the store anyway, since drops are plentiful and it's easy to craft and/or trade duplicates.
Besides, from the snippets of sales figures I've seen from the store, Valve has probably been making way more money from selling items than from selling the actual game for a long time now, more than enough to support continued development just from that source. This really won't change the status quo in that regard.