Yes, the whole contest is subject to change. Can easily make it just one contest, probably ETO, with a shorter submission time. I have a couple of battles that I could submit for consideration as the battle for the design. I wanted to gauge the interest in such a contest because I would need to line up some judges for the contest. In comparison to the first MwT where there were rapid fire posts by interested people intrigued by the idea, the response has been very limited. In the first one, people wanted to participate without any defined contest as designers and judges. In the seven years since the first one, people's lives have filled with other needs and wants. If only five people submit designs then those five might also judge the event, play testing the others' designs and rating them for several criteria. The contest is not limited or restricted to the material in the attachments.
The two I participated in were enjoyable endeavours, but I think the novelty of it was the attraction. The first one was a genuine attempt to answer basic questions about scenario design - i.e. how much variety could you possibly get from a single historical event? The answer was a most pleasant "lots" and produced IIRC over a dozen good Carpiquet Airfield scenarios. The next one, on Norway, I interpreted as a follow up question along the lines of - can we recreate the fun of the first one. I thought the answer was no, frankly. The historical situation was interesting, but the history provided seemed vague, and a little more broad, so naturally the designers came up with a variety of scenarios. I think at that point the question had been resolved.
If there was a real impetus to do another contest, you'd need to either be answering a really compelling question, covering a really fascinating (and under-represented) historical action, or perhaps be offering some terrific prize/incentive. My opinion (only) is that you'd need to be *more* specific about things like parameters, rather than *less* specific. I suspect many scenario designers tend to be secretive about their ideas, so expecting someone to put up ideas to a general vote may not be realistic. For every designer who thinks they have a great inspiration for a scenario design, I'll show you a designer who secretly dreads that someone else is working on the same subject *right now.*
The one contest I ran on my own for the ASLSK wasn't even based on a historical action, but on a set of map parameters (i.e. can you design a scenario using 4 boards end to end, ala the original Squad Leader). Gimmicky? Perhaps but was also interesting to see what people managed to come up with, and they ran the gamut from Crete to the Spanish Civil War, to Northwest Europe to the Russian Front. So not all contests need to use a common historical event as its basis.
Basically, it's like a thesis for a term paper - find a question you want answered. Can you design a scenario with not one, but two parallel rivers? Can you design a scenario for four players? etc. The question posed in the attached documents - can you find a historical action to represent in ASL? - has been answered literally 4,000 or 5,000 times including third party publications.