The following is not knowledge of Sony's doings, but rather experience from software companies (I've worked both as a developer and as a tech reporter in the last 15 years).
Memory problems, e.g. codecs/encoders crashing when they reach their 2 GB RAM limit in 32bit OSes, are usually deeply engraved in their architecture. Architecture changes are very difficult, if not impossible in legacy apps. Vegas is already 13+ years old, meaning that the bulk of its "under the hood engine" is currently in maintenance. The engineers that wrote this complex piece of code probably don't even work for Sony anymore. This "low-level" knowledge usually comes directly from the people that wrote that code (documentation is rare among start-ups and smaller companies -- which is what Sonic Foundry was before Sony bought them).
So basically, I would not expect any 32bit version of Vegas to fix these issues. I mean, that's the No1 complain of people here on the forum, and yet, Sony hasn't fixed these issues in the last 5-6 versions! What this probably means is that it doesn't make much logistics sense trying to fix something so deep, when 64bit is already here code-wise. Vegas Pro already has a 64bit version, but Platinum doesn't. In my opinion (again, this is just an industry experience-based reply, not knowledge-based one), the only way the situation will get remedied is by, eventually, releasing a 64bit version of Platinum. So if I were you, I wouldn't wait for that dreaded "low memory patch" that has never arrived. Why would it arrive now, when 64bit is a much cheaper/easier transition for Sony?