There really isn't any issue, however when the Product Managers started looking at where technology is going, based on feedback from customers on how they will invest in hardware, the large majority stated when going to Windows Server 2008 they would be going fully 64bit and not remain on an x86 platform, due to the fact that it really is the way all software is headed now.
So when it came time for development and QA processes, it made more sense from QA/Dev standpoint that the majority of the efforts should be focused on the x64 instead.
Again, this isn't to say that it will not work on a standard 32bit server, it just means that if you do have any issues, you won't get the level of support you would were you on x64 platform. So for instance if you find a bug you would be asked to upgrade the server to x64 to eliminate any issues that an unsupported and untested platform might cause
https://www.linkedin.com/in/alex-allen-turl-07370146