If someone doesn't have enough DKP for minimum bid they either 1) spent all their DKP for an item they REALLY wanted recently and not saving enough for min is their own fault or 2) new or poor attendance.
I have seen too many people come in new, go very negative in the DKP department and as soon as they were geared enough to get into a different guild, bail. I know that some of the new guys would stay, but every time a guild gets used like that it leaves a bad taste about new guys. The only way to avoid that is to wait until they are past their trial period. Hell, when I first started raiding, I had been with Conventus (at that time they were NaG) for over 6 months as a non-raider while Gump was their main off-tank. When I started raiding, I had to wait 2 or 3 weeks before I was allowed to bid on anything, even though I'd been around, farming guild mats and they knew I wasn't going to leave. I watched priest gear get DE's or left rotting because I couldn't bid yet. It's the way it was and by not whining about it they knew was being serious about raiding.
I've stating before that I liked loot council because officers discuss this shit privately and no one can really be a loot whore, but DKP has advantages, especially in being quick. Our officers are very concerned with being fair and trying to figure out some of the gear would take them forever.