There is a real obsession among contributors, not just in MAN but elsewhere too, to make fantasy terminal reshuffles. Often these involve nicely boxing and categorising alliances and low cost/legacies/charter etc.
In the real world, this doesn't necessarily make sense. Low cost carriers don't necessarily "love" the bus station look. The "bus station look" was lead by the airports in a bid to woo low cost carriers. The LCC's don't explicitly want that. What they want is efficient turn arounds and infrastructure that support their operation. That is principally why they often (far from always) use steps.....so they can disembark and board faster. Incidentally, many airports don't charge for airbridge use, MAN is one such example.
There is also there mis-perception that the LCC passenger doesn't want much in the way of terminal facilities. That may have been true back at the start of the low cost revolution but it's far from the case in 2020. As someone alluded to earlier in the debate, the airline market has become much more homogenous. In other words, the passenger who uses Vueling to BCN or Norwegian to ARN are often the same passenger who uses SQ to SIN or LH to FRA. Their needs don't tend to change very much, if at all, with their change in carrier. Indeed, one of the reasons easyJet moved from T3 to T1 back in the early 10's was because passengers didn't particularly like the limited retail/leisure experience in T3 which, at the time, were quite limited. I should also mention that the plan is for easyJet to move to T2 in 2022, at least that was the plan pre-pandemic.
Its also worthwhile noting that from MAN certainly, you will find that it is the leisure traveller, often travelling on a LCC, that spend the most in the terminal.