Not if the changes they made to the overall system which they had to do for both builds were optimized for Intel and therefore not written as cleanly or nicely for PPC causing it to act slower or crash more often. Software coding is a tricky bit and its very hard to try to have one or similar pieces of code running on completely different systems. I mean its hard enough optimizing the code to run smoothly on one let alone both simultaneously. And if I was in the position of which to optimize for I think its obvious, the ones who shelled out the extra money to buy brand new Intel machines and entrust in Apple they will get faster (since Rosetta was far from a quick solution). If you just upgraded your hardware I'm sure you would be pissed if after paying all that money just now its not even being optimized for you. I mean its been what two years since Apple announced the switch? I know a lot of people still have PPCs cause rarely do people buy new computers every two years. But this is the start of sort of regular cycle for buying new computers in the 3-4 year period. When Leopard comes out I'm sure it'll be even slower (half due to the extra specs needed, and half due to optimization). So that at that point when Christmas rolls around many PPC users will feel like its time.My (both PPC) Macs seem to behave fine under 10.4.9 as well as 10.4.10....
Besides, at the risk of being called a fanboy (jigga, please), if Apple were releasing very optimized Intel builds, it still wouldn't cause the PowerPC builds to actually get slower than the previous PowerPC builds. It would just cause them to not get faster.
They may be starting to show their age only now, but its not going to get any better. I think Apple has made a very nice transition seeing how new software for Apple works on PPC and everything. But you can't expect everything to be optimized for PPC years down the road.