Lets proceed with caution!
It's my opinion that the complexity has been institutionalised into a structure of Companies (as well as their procedures and documents) to the extent that any 'campaign' for change is likely to produce minor revisions only, and they in turn are likely to be promoting the political expedient of the month and will then quickly introduce a new raft of problems to replace any it solves!
Its also my opinion that the creation of ATOC, ATOS, RSP etc was rushed in preparation for Privatisation and that that haste is as much the villan as any lack of will or ability in the industry. However, it appears to have reached the stage now, that the structure is so established and suffering from rigor-mortis that meetings between these bodies are now very poorly attended, perhaps there is little expectation that much can be achieved (rather than a lack of vision). Disinterest and/or defeat might have set in.
But where does that leave us? Many of the complaints seem to be aimed at Company-specific products (Advances, Rovers, widely varying Restrictions) which suggests that the pressure to manipulate market forces is strong. As long as that is the case for all Operators, then perhaps the interface with the passenger should look and work more like a market. At present this is a mix of TOC-specific fares and those managed through RSP and its famous ORCATS (as long as we have companies whose existence is predicated on 'ORCATS raids' them I'm convinced that we have a structural failure). If RSP became more flexible in allowing dynamic pricing by TOCs and including sales across TOCs, and it became more pro-active in ensuring a consistent and available interface, and a more transparent and accurate method of distributiing revenue across Operators, then we may find that ATOC can concentrate on the practicalities of inter-Company operation and the ORR can concentrate on the standards and targets achieved set by government.
[Other people on here will have their own widely different responses to your question]. But try saying any of this to your local MP and (s)he'd wish you just wanted a photo at the local flower show.