Remathilis
Legend
I'll have to concede the point to you, since my knowledge of 4e is still mostly hearsay.
That's not my understanding of the situation but I'll freely admit to a bias of maybe "absorbing" a few more "I have fewer options in 4e" posts than I may have "I have more options in 4e" posts.
But even conceding that point, taking multi-class out of the mix is a pretty big concession in itself.
I'll take a stab at trying to explain "less vs more".
Lets say you walk into a game (new player) and you ask the group what you need. "We need a healer" they reply. "Core Rules Only."
In 3e: you have a few options: You could be a cleric, druid, bard, or paladin. However, there are many sub-optimal choices there: druids need to prep cure spells so many of your spell slots would be tied up in Cure X Wounds slots. In addition, you'd lack many of the powerful status-removers (Restoration, Raise Dead) or have the delayed in level. A bard would spontaneously cast Cures, but they have slow progression, limited spell choices, and fewer status-removers than a druid. A paladin has lay hands, but unless your a wand-weilder, you are pretty much useless at additional healing. You could do a cleric, but you best be positive energy channeling or you're stuck with 1/2 your spells slots CXW anyway...
So you settle on cleric. Great. You decide you want to kick a little ass while you heal, so you chose Kord as your deity. You also want a martial weapon (greatsword looks nice, and its Kord's Wpn of choice). How do you get it? Well, you could multi-class into fighter, but that slows down you spell progression, and unless your keeping even levels (which is the death knell of a caster) you are now restricted to human, half-elf, or dwarf (favored class). Or, you could blow one of your 7 feats to take MWP: Greatsword.
4e: You need to be a healer, so you have head straight to the leader role. You have two options; cleric and warlord. Either one grants you holy/inspiring word, so you can make healing surges kick in when you want. Clerics are better at healing, warlords at buffs (both are no slouch though at the other). So you opt for cleric. You still want to kick some ass, so you invest one of your 7 HEROIC TIER feats (7 before 10th level) in Greatsword, and look at the "battle cleric" build. You choose any of the eight races (though dragonborn, dwarf, elf, and human make the best clerics) and you are all set. If you want, you could begin to invest some feats into multi-classing fighter or paladin powers as well. You make sure to note which rituals you'll need (remove affliction, raise dead) and talk with the wizard about sharing them...
While there is less overall options (2 classes vs 4, no free multi-classing) more of those options are "worth-while". Over the long-run, you can craft your priest into a battle-hardened war-priest (paragon path) or you could retrain him into a better healer-defender type. You could even had gone warlord and picked up ritual caster and done everything a cleric does, including raise the dead! All the races are viable (even those without wis bumps, none give a wis penalty) and you can use feats to customize your PC better because there are fewer "must have" feats (Precise Shot, Power Attack, Weapn Finesse, etc) and more feat slots.
However, if you liked the idea of having open-book customization and routinely took cleric3/fighter2/warpriest3/radiant servant10 as a build advice, you're going to be choked by 4e's restrictions. The more you liked to fiddle/stack, the less 4e is customizable. However, if you want options for expanding PCs "within their role", 4e can't be beat.