Can I make a suggestion? Well I can, but perhaps a better question is whether a suggestion would be welcome.
Instead of requiring the players to post by order, perhaps you should change the order in which people go by their posting order. This would require you to roll the bad guys in mass, but otherwise preserves the initiative. You could also implement deadlines for posting to keep combats moving.
Let me give an example of what I mean: Bob, Steve, Sue and Dave and first level adventurers and are fighting a single kobold. The initiative totals are:
Sue 17
Steve 14
Kobold 11
Dave 8
and poor Bob at 2
The DM would post the initiatives and Sue and Steve would have two days to post their actions before you wrote the kobolds action and the summary/result post. Sue and Steve's action order would occur when they posted rather than by the initiatives and if they didn't post they would lose their actions.
After you posted everyone would get the chance to act, again they have two days and again they act in the order which they post. In two days (or after everyone has posted) you post the summary/result and the kobold's action.
I think this would keep the action moving without waiting for people to post, it follows the spirit of the initiative rules with the only drawback being the bad guys all having to go on the same initiative.