Even if it was objectively better, which I share the opinion of the posters above, that is isn't. I don't like the idea of forcing something, which would actually weaken the Bitcoin network. Let me just elaborate on this; We ideally want as many users running nodes as possible, right? So, by restricting nodes to only Tor would reduce the amount of people that run nodes, effectively weakening the network. Besides, Tor is optional, and works well with running a node. If a user has a specific reason why they want to use Tor, they can.

Even if, running a node on the Tor network was objectively better, which I think is probably up for debate by those in favour of it, I don't like the idea of forcing users to use a specific platform which isn't bulletproof in the first place. Tor is as anonymous as the end user makes it, and despite it being a pretty good out of the box solution it itself is susceptible to attacks, and if we are relying on what effectively is a third party program to run a Bitcoin node, any outages or vulnerabilities would have the chance of knocking out all Bitcoin nodes for a period of time, which is definitely not great for Bitcoin in general.