We are about to move house and are going to do a big renovation, which offers lots of potential for fun with automation! I'm looking for advice and recomendations on the best approach for a brand new automation project (rather than the gradual additions I've made over time in my current house).

My current house is automated around a VeraLite controller, with LightwaveRF lightswitches, Fibaro (zwave) motion/temperature sensors and StellaZ radiator valves (also zwave). I also have a server running HomeAssistant for a web user interface, custom automation and control with Python. Finally, we have Google Homes for voice control and playing music.

Generally this has worked fairly well for what we need, but none of it is trouble-free (by any means...). Most of what I have selected has been dictated by what I have available (wiring, etc.), but with the renovation, there is potential for adding in infrastructure for kit that has fewer compromises. I have a reasonable budget set aside for automation (~10-15k), and I'm happy to continue developing DIY / bespoke automation approaches (actually, would rather this!).

What I would like:
A system that can be dimmed, uses wall switches (or is compatable with them) and can support multiple LED ceiling downlighters. I wondered about Philips Hue bulbs, but that could be an expensive option and running them alongside wall switches seems to get complicated. I do like the idea of setting the colour of the bulbs, even if the novelty wears off quickly... I would perhaps consider LightwaveRF again, although I've found the switches can be fairly unreliable (both in not responding to commands and simply breaking), you can't monitor the state of the switches and have fairly modest power limits (e.g. any more than 5 halogen bulbs will blow the switch up).

For switches, I wondered if any reliable solutions yet exist for a touch panels?

I really like being able to set the temperature of each room individually, which I can currently do with my StellaZ system. However, the StellaZs need their batteries to be changed regularly, direct control with zwave isn't straightforward, they can only 'wake up' every 4 minutes (which isn't great for a responsive system) and report temperatures in whole degrees (I think you need at least half a degree reporting for maintaining a stable temperature). Also, the attachment to the valves can be a bit variable, and can let hot water in when the valve is supposed to be closed. Are there any reliable alternatives out there?

Occupancy / Motion
I currently use Fibaro motion sensors to switch on lights in hallways and landings, which are battery powered. As I'm renovating, are there any options for hard-wiring motion sensors? Are there any systems that use motion sensors entirely in place of lightswitches (could be problematic if people stop moving... unless someone has come up with a solution - perhaps temperature sensors too)?

I would like external cameras and a door entry / boorbell system (perhaps zwave enabled?). There seems to be a lot out there... I've never found a good way to monitor cameras that can be easily integrated with the user interface of the automatiob system.