Over here to check it out. One of the key answers that I read was that Gold members are distinguished from Silver by how much they can customize. I think I stated this in my last post, but most of the fun in Champions Online is from making your ideal super hero.
Still, many people make similar power choices, and archetypes are repeatedly stated as not being all from the same power set (though early ones will be predominantly of one power set).
If anything, I think they will get more people playing. It might also give them the incentive to pump out more adventure packs and power sets. Both of these are "free" to Gold members, and paid for by Silver members. This can cause Silver members to pay, and Gold members to keep their accounts active.