They haven't complicated the process. It's inherently complicated in itself.
Some people want better seats, some don't. Some are happy to spend more, others aren't. Some want to sit in group, or add or delete people, some don't. Some are renewing, some aren't - but FFC are still allocating them seats until told otherwise.
There's 37,000 people to seat, give or take, and people are being allocated according to tenure. And FFC are meant to know exactly what every member wants?
You can't throw the seats open for everyone to pick for themselves, that won't work either. They're doing it the most workable way - allocate seats so you get something vaguely comparable, and give the opportunity to move later.
Their main objective is to get people renewed first, then deal with preferences later, for those that have them.