I don't think that asking for more than 4 VLANS on a so-called enterprise router at a cost of 200-300€ is excessive. And as I mentioned before, there's NOTHING about this VLAN limitation either in the Dlink documentation nor when I ask the support. In fact, the DLink EMEA-support thought it was a bug and should be like that in the first place and advised me to upgrade to the latest firmware. And I actually did my homework, I researched the router before I bought it through various reviews and forums - even now - non of the English-speaking forums mention anything about the VLAN-limitation of the any DSR-series routers.
I find this limitation very odd as even some <100$ smart switches (e.g. Netgear and TP-link) are more than capable of managing way more VLANs than DLINK, which again, although it's a router, cost 3 times more.
Looks like smth. that has been impemented as a quick hack in order to compensate for some other already advertised funcionality to me. And boasting with the ability to support up to 65 VPN-tunnels, but limit the VLAN to 4, which is less than those 8 ports available, just proves my point.