Hi,

The real answers would depend on what feature you use in the Model Admin tool when developing your RPD.

Keeping it short: the Semantic Modeler is going to be the future and, at some point, the Model Admin tool will disappear.

If you use the various tools in the Model Admin tool, you will not find those in the Semantic Modeler. On the other hand the Semantic Modeler has a native git integration, making it extremely simple to version your models and to work in multiple people using git for merging etc.

For the model itself, both do the same things because they both produce the exact same file to deploy on the server.

Because you aren't starting from scratch but already have a RPD, you first need to import it in the Semantic Modeler and see if it is imported correctly (sometimes it does fail). Then it's a different user experience: if you are used to the Model Admin tool, you will need some time to adjust to the Semantic Modeler and develop new automatism in how you work. The Semantic Modeler requires more clicks, because it's web-based. But you more easily can modify the json defining the model for mass updates or changes.

While technically possible, you should avoid keep jumping from one to the other: decide which tool you are going to use based on your internal processes and stick to it. If you switch to the Semantic Modeler, you should consider adopting versioning in git and evolve your process to be based on that.

It's difficult to talk about "improvements", it all depends on how you use the tools: some users will see the Semantic Modeler as an improvement, others will miss too much a tool (like the rename wizard) and will not be able to use Semantic Modeler for now because it's missing.

You must try it and decide by yourself, that's the only way to decide if the Semantic Modeler is good enough for your needs and processes, or if you have to wait another iteration.