Andrew Jung wrote:
Is there really anything in this release that would make it Lion only?
Guessing: iOS-compatibility. Apple has put _a lot_ of effort into bringing this change about quickly and decisively.
I recommend sending feedback to Apple via the mechanism Terence listed above. (I remain agnostic on the issue, but I am always in favor of communication.)
My guess is the enhancements to the tools means changes at Core Image level along with the iOS material as well. It's moot though...
And of course, you're not forced to do anything. Look at what upgrading gets you in terms of features. Look at what it costs you - money, upgrading the OS, etc - and if you find the price of upgrading to be too high... don't. It's a simple cost/benefit analysis.
There are a lot of APIs in Lion that either didn't exist in Snow Leopard, or were substantially improved in Lion.
With Mountain Lion shipping in July, one would figure if Aperture is going to support two OS X versions, they would be 10.7 and 10.8. Trying to support 3 OS X versions in one release of a product is a lot of work, and staying two OS X releases behind starts to trend toward being a "laggard."
I suppose that is true, I guess, I just would have liked it if the new library format would have been made available to SL so that I would have been able to still access my photos on my apps that don't support Lion (aka Rossetta) when I boot up with my SL partition.
That said, I think it might be prudent to wait out for the next version before I upgrade my libraries to the new formats. Wait for all the bugs to be worked out first.