Are you saying that Dan Meis is incapable of designing a ground with retractable seats?
Of course he can and it can be done without leaving a massive gap between the pitch in football mode. But it will add more expense and the unanswered questions are 1) would we ever hold another athletics event after the commonwealth games and 2) will the city even be awarded it in the first place?
Starting with point 2, I've seen on this thread people saying Manchester and Birmingham already have the facilities to hold the event and while yes they may have the majority of the venues there is only one stadium in the country capable of holding the track and field currently and that is the Olympic Stadium.
Unless it is held there then a new stadium will be built or significant changes (be it temporary or not) will be required to an existing athletics track to raise the capacity to the 40k minimum level. I don't see how people can automatically say Birmingham will be awarded the games as the biggest part like Liverpool would still need to be built.
If we do have a multi purpose stadium capable of holding track and field events, it will by far the largest stadium outside of London. The thing is there is only one big meet in the UK per year and that is now called the Anniversary Games. As its name suggests it is about the Olympic legacy so could that take place in Liverpool? A lot will depend how this years World Championships go, apparently they are looking at a conversion cost of around 8 million and a time frame of 2 weeks, that could mean West Ham playing somewhere else at the start of the season. Here is an article on the situation:
www.theguardian.com/sport/2016/nov/02/west-ham-stadium-losses-retractable-seating-problems
Should there be any problems that cause the conversion to cost more or take even longer then there could be an argument for another stadium to host the big athletic events in this country, even if it was on a rotating basis.
We would need to be sure though that the same problems will not exist in any proposed stadium we put forward. The converstion would need to be cheap and be able to be packed away in a short space of time.
If it was to be just a one off event then surely it would be better to have the games first and then finish the stadium afterwards. Although that would delay us moving in. We would need a massive subsidy from the council to even consider this.
My personal view is that it is not worth the hassle, yes host the opening/closing ceremonies if thats possible but let someone else deal with the rest. Or even better we don't get the games in the first place and that can be the end of the discussion. However a bugbear of mine is how it can be dismissed impossible or not workable with football being the primary focus unless you have a great big oval type stadium. That does not have to be the case and if the council are prepared to stump up 100 or so million (or at least reduce the amount we pay back per year to that value) if we get the games then it is worth considering if it can increase revenues and elevate our stadium from 'that's great' to 'god damn thats the bomb!'