Corona team: as someone who works more on your side of things (making products) than the user's side, I completely understand the complexities and compromises behind decisions like this.
But I've also learned a lot about communication with customers, so I hope this helps you.
If people think the roadmap means as a promise, the uncomfortable truth is that is what it means. It doesn't really matter what was your original intention, it doesn't matter if that makes sense or not from a development standpoint (I know I would seldomly make promises, as the development process is messy by nature) ANY miscommunication is your fault, or rather, your responsibility to fix. It serves no purpose to say "well, that is not what the roadmap is for" People's interpretation of your actions become reality, regardless of how close or far they are from the truth.
You may say internally BUT WE EXPLICITLY SAY THIS MIGHT CHANGE! It doesn't matter. If people understand something else, you need to do something different. The customer is always right in the very real sense that what the customer believes becomes their reality, so you need to accept that.
I won't even question your intentions, I know decisions are a delicate balance of thousands of factors and I know you are trying your best. I trust capitalism and I know in the long term the best for your company will closely align with what customers want. I also know you have orders of magnitude more information than us. Market trends, future developments, Long term strategy, Usage statistics etc. People in the forum represent only a small portion of the data, a very important portion, but not absolute.
So, even though my most wanted features are not part of V6 (PBR and tone mapping) I trust the vision of the product, that vision has consistently yielded good results over the years.
My advice to you is to make an even bigger effort in communicating that vision, and how your decisions work towards the vision, It might seem redundant as most of that is obvious to you, day to day stuff, but user don't have access to that information.
Another advice (and this might be difficult because of corporate strategy, but think it's worth it) is to make development and experimentation exciting to users. I think Fstorm does an AMAZING job at this. That engine is not production-ready, it lacks essential features, but the developer is good at making people feel excited about what is to come. You can see how most of the "most wanted features" are borrowed from Fstorm. He makes people excited through good communication.
Example: You say you developed a new sky system that works amazingly well. We've seen 0 evidence of that. No one is excited about that. You can make us excited with a couple of posts showing how that produces better images.
I hope this helps :)