If you can handle JavaScript better, then write your rules for openHAB in Javascript:
Browse a bit here, if it suits you: openhab2-javascript/SimpleRuleExamples.js at smarthome-To-openhab.core · lewie/openhab2-javascript · GitHub
There isn’t much documentation yet, but if you know JavaScript you’ll be fine. If you have any questions please contact us here.
To 1) There you must already become more concrete. Doesn’t Insteon PLM - Bindings | openHAB work correctly?
To 2) A system only seems complicated as long as you don’t know too many answers yet… As I said, maybe the freedom to use JavaScript already helps you?
There are always arguments for or against it. But even with a change you will encounter limits, other limits, which you were not so aware that they exist. I mean, try to address the problems first and then solve them one by one. Go into the depth, we help with all problems.
Why should you have to rewrite your existing DSL rules? Absolutely not! DSL will be around for a long time to come. Even if it can be that they will be announced sometime, the time will be very long until DSL Rules will stop to run in openHAB.
New ones you can write e.g. with JS. And rules that have to be changed can be rewritten in JS.