Import maps isn't standard yet, and looking at the repo they still have a few kinks to work out. For broader reference, WICG doesn't standardize HTML -- it incubates interesting proposals, which can then be merged into the HTML spec. That hasn't happened for import maps, and this feature is not yet standard. Chrome tends to ship proposals eagerly, to get early feedback. This is a great for people to experiment with it.
Since you mention bundler free web development: One of the proposed use cases is import maps + http push, and I know many people are excited about this. dhh spoke about this technique on twitter, and it brought a lot of attention to this bug. This technique will likely not be viable in the long run, as Chrome is dropping support for http push and they do not plan to support push from HTTP/3. You can refer here for more details: https://groups.google.com/a/chromium.org/g/blink-dev/c/K3rYLvmQUBY/m/0o4J1GEjAgAJ Something else, potentially equivalent, may take it's place, but it is hard to know right now. Import maps is independently useful. If you were excited about this -- then this solution may still take a bit of time as alternatives are explored.
Bundle "free" development is currently under active discussion. There is contention about whether or not bundling should be integrated into the browser, as the network requests may be too costly to ever move away from bundlers. There is disagreement on this point, and research is ongoing. IETF and WICG are looking into this, and presentations have been made to TC39 as well. Alternatives have also been discussed. You can take a look at the following repositories for more info:
From our side: at present, there isn't bandwidth to eagerly implement this proposal at the cost of other high priority work. Coupled with the experimental status, the shifting space of complex multi-resource applications, and the implementation complexity which may interfere with ongoing work, it doesn't make sense to implement immediately. It is on our radar however, and we will certainly get to it when we can. I am doing a pretty large push on modules this year, and it will likely be within the scope of that work. I have a few higher priority issues to get to first.
OK, phew, the last thing. I am not sure what you mean about "native code reuse". Perhaps you mean portability between server and frontend code?