Landing speed a321 and a380

The landing speed depends on the mass of the aircraft, the wing area and lift coefficient. The A380-800 wings were designed to be suited for an even larger A380-900, so the A380-800 as we know it (-900 was never built) has wings larger than it needs to. The A321 on the other hand is a stretched version of the A320 with higher mass but similar wing area. This means the small wing on the A321 has to work extra hard, which is why slotted flaps have been added.

To summarize: A380 wings are larger than they need to, A321 wings are smaller, and therefor the landing speed of the A380 might be lower than that of the A321 even though the A380 is of course much heavier. But the approach speed depends of course on how much fuel and payload is loaded.