So, how would the concerns of the millions of demonstrators be addressed?
Do you think it's fine for the elected to give himself unlimited law-making powers?

That's where having a well written constitution comes in, something with the ability to remove or impeach someone who abuses their powers.

The solution is not for the military to play kingmaker.

Quite.
As I understand it, the plan is to draw up a(n amended) constitution, have a referendum on it and then have elections.

Who would impeach him if not the Army?

Morsi got himself elected through a democratic process and immediately dismantled or overrode that process. No motter how well written a constitution may be, it still requires someone to police and enforce it

Wouldn't it be a matter for the courts or, at the very least, some sort of parliamentary scrutiny body? Morsi being impeached via a civilian legal process, given a hearing and then removed by a number of high-ranking judges, would probably have caused far less unrest than the army wading in and arresting half of the Muslim Brotherhood.

For that to have been possible, there would have needed to be some item in the constitution or other law via which Morsi could have been impeached.
As I understand it (which could be wrong), the constitution was inadequate and Morsi took advantage, granting himself power to edict any law ... hence the need to draw up an amended constitution prior to starting the election process all over again.

Yeah, I get that (in fact, I mentioned it myself a few pages back) but cod'ead seemed to be saying that, even with a well drafted constitution, it would be down to the army to remove/impeach the president.

Didn't he also remove/replace the sitting judiciary too?

Given it was Egypt's very first stab at democracy, it's almost inevitable that there would be anomalies. But if the law was being redrawn in favour of one man/organisation, it still leaves the question: who would have the strangth and power to stand up to such abuses?

Ah, apologies.
With a properly-drafted constitution, yes, I agree it would be a judicial process ... but, I guess, always with the army as the ultimate back-up to ensure compliance with the judicial outcome.

I would suggest that the civilian police force should undertake the enforcement role. The army getting involved should be the very last resort.