Remote controls that are placed in an orderly (!) manner.
Are you a nerd, a stickler, or both? :)
Primarily, it is important to me that I can lower and raise all the roller shutters or venetian blinds at once. The simple reason for this is that in the evening I don’t want to walk through all the rooms and press every switch. However, I naturally want to have the option at midday to control the individual roller shutters per switch in every room. That is a MUST HAVE for me initially. To support this MUST HAVE, the central switch (about €1000) would be sufficient.
First of all, I am not very keen on lumping shading and darkening together and I remind you of my advice not to interfere with automatic impulse generators by using switches – they get along much better with push buttons. I see it as sensible for you to set up four control circuits: one for all darkening and one each for the shading East / South / West. Don’t forget to secure the automatic system at the terrace exits against locking yourself out. Also consider how you want to transmit the commands (and status messages): only via LAN/WLAN or also via GSM/UMTS. From my point of view, you should make the PLC (don’t forget access security!) best accessible via LAN and WAN.
For me, this has the consequence that I have to equip all electric roller shutters and venetian blinds with a radio motor and don’t have to lay cables from the switches.
You have to supply power to all motors anyway. The branch lines from the motors to the switches are about one and a half meters each. I believe you still have a bag full of misconceptions about the whole project: on one side too simple, on the other too complicated.