I've done a 16 teamer for about 15 years. I think it's great. We us 1 qb, 1 rb, 1 wr, 3 flex, 1 k, and 1 def. I think we only have 4 or 5 bench positions. There is a ton of strategy involved, so I love it.
I've been a part of a 16 team league, we start: QB, WR, WR, WR, RB, RB, TE, K, DEF, 4 bench spots.
It gets tough during bye weeks, but it happens to almost everyone, generally enough QBs are floating around because the benches are small.
I'd advise not having a flex, because not enough RBs are available to everyone and someone can get a huge advantage. However, 3 WRs slots are easy to fill.
Think of it this way, you're basically having two NFL teams worth of talent on each fantasy team, so 2 RBs is all you can really have and 3 WRs is a good amount.
I like it, it makes it really competitive and also makes it easier on who to start week to week with only a four person bench. It definitely puts more emphasis on the draft as free agents that are well known going into the season aren't as readily available as they are in 10 or 12 team leagues.