Aggressive pre-order campaigns aren't really anything new. It's all but standard for companies to offer some sort of bonus outfit, non-combat pet, or other minor bonus to pre-order customers. Case in point, Syp noticed that Star Trek Online preorders through Amazon will come with a free Borg crewman. (No word on whether they will try to assimilate you and/or your ship.)
Most likely, though, Cryptic isn't done yet. They launched Champions Online last month with a preorder discount on 6-month and lifetime plans (including a weird situation in which the plans "sold out" and then Cryptic decided that they'd take money people were extending in their direction after all) and guaranteed access to the Star Trek Online beta. Meanwhile, Turbine just went live with yet another Welcome Back Week in LOTRO, in part to promote at pre-order campaign in which current players generally don't have to pay for the upcoming expansion.
(As someone who juggles a tight time/money budget for MMORPG's, I had made a deliberate decision to let my subscription lapse until the pre-order deadline in case there was free welcome back time to be had. The winner: it's me.)
There are some good reasons for the pre-order model. For less-known games, strong pre-orders might help secure increasingly limited retail shelf space. (WoW is the only major release I can think of that does NOT go to any effort to secure your preorder business, perhaps because they don't need the help.) There's also a psychological hook to getting players to make the decision to purchase; you can cancel a pre-order with most retailers, but that requires you to actively change your mind.
The downside, of course, is that all of this creates a high pressure sales pitch. If you don't sign on the dotted line before the deadline, you miss out. The publisher is counting on the pressure to convert some maybe's into yes'es, but it can also convert wait-and-see into "oh well, missed it". Why would I jump onto Aion or Champions right now, having passed on their pre-order periods? Might as well let the server issues and launch patches settle out; there's sure to be a free trial at some point down the line, so I don't need to gamble $50 on the games sight unseen.
Now we're getting higher stakes. It turns out that the mount that was discussed as part of LOTRO's $20 RMT "adventure pack" is actually a pre-order item. After Oct 31, the pack will only include two character slots and the shared bank (which, in my view, will almost certainly be offered for purchase or expansion through some other venue - who codes that much GUI for a bank that only has 20 slots and will only be used by a small subset of players?). If I'm reading these two seemingly contradictory Turbine quotes correctly, the mount will be banished to a $40 bundle with the expansion (the one that current players generally wouldn't have to pay for) on October 31st. A permanent mount for all of your characters, which bypasses a pair of in-game gold price tags and a major rep grind in Moria proper, is now a pre-order bonus.
If any developers are wondering why us players are so distrustful of RMT, this sort of escalating pressure to spend more more more now now now, better act before it's gone, would be part of the reason.