Agreed. I rarely find the guardrails of plan to be necessary; I basically never use it on opencode. I have some custom commands I use to ask for plan making, discussion.

As for subagents, Pi has sessions. And it has a full session tree & forking. This is one of my favorite things, in all harnesses: build the thing with half the context, then keep using that as a checkpoint, doing new work, from that same branch point. It means still having a very usable lengthy context window but having good fundamental project knowledge loaded.