The iPad Pro 9.7" misses out on one fringe use case where you may want to interact with 3 apps at once on sub 10" screen. I doubt that will obliterate many use cases.
It still has a super fast A9X chip, amazing screen (called perfect by many tech reviewers), great speakers and Apple Pencil support. The 10.5 is a better device for me, but don't discount it.
Also, if "age" means slow down, then no. The iPad 3 "aged" rapidly because it's A5X stuttered and lagged after just 1.5 years. The 2GB of RAM will only mean more frequent refreshes with apps and safari tabs. It will be able to perform well for years to come. On my current Pro I can have 5/6 tabs and another 3/4 apps open easily. I can go beyond that, but it depends on what apps.
The fact is that 1 year after release it is missing a feature that comes in its FIRST software update. Whatever way you want to spin it, thats not great, doesn't bode too well with what next year's iOS will be missing. I got told tome and time again that 2GB of ram would last for ever, yet we are already seeing a limitation.
It will loose iOS support sooner than the 4GB 12.9 inch pro as well. The 9.7 inch Pro should have had 4GB of ram, I'm glad the 10.5 does as I will be upgrading to it.