I would assume that pure lantiq devices (SOC and modem) will be relatively easier to support than hybrid (ipq40xx + lantiq (VRX518/ PSB 80518) solutions as the AVM Fritz!Box 7520/ 7530 (those already exist for VRX2xx, e.g. Netgear D7800 or TP-Link Archer VR2600, neither of which support the VDSL functionality, although that 'should' be possible). But that's obviously guesswork at this point, as neither of these super-vectoring capable SOCs/ modem chipsets are supported yet.
However, given the prices for used VRX2xx devices (e.g. BT Home Hub 5 Type A, some of the supported AVM Fritz!Box variants (3370, 7362sl, …) or the aforementioned O² Box 6431), which are in the sub 10 EUR range plus shipping, I would definitely go for one of those, if you don't need super-vectoring now - and just wait and see for the situation to pan out for super-vectoring.