I don't agree. Cases like the Dan A4 and Louqe S1 have the GPU fan really close to the grills where they can draw fresh air in. This is the same for the CPU heatsink.
So long as you choose a blower design for the card and a top mounted fan heatsink for the CPU, it will be fine. But trying to use those 2 or 3 fan card designs will obviously throw hot air all around the tiny.
Also as you mentioned, with liquid cooling, you can really shrink the dimensions of the case while transferring the heat elsewhere. No need to use a huge tower style air cooler.