Fair point.
If within the beta test we see that the demo accounts are fairly standard from the start - that may be a good option to go with.
On the other hand - we still want to give the traders an option to choose how much and what they want to start with. The idea has it's Yes' and No's, don't you think?
Perhaps, after registration make a pop up "Want start with live or demo" if choose "demo" give an option to choose how much demo money client want and select exchanges he want for the demo. Super easy and simplified.