I should really have said it's difficult to have a themed and effective character in CO.
Some powersets are rather well-rounded. Unarmed (a sub-group of Martial Arts), for example, has melee attacks, ranged attacks, weapon attacks, bare-handed attacks, offensive buffs, defensive buffs, debuffs, and a self-heal. Several of the Sorcery and Supernatural powersets are equally well-rounded.
But, like I said, the elemental sets are horribly one-note and not well-rounded at all, while in CoH you had a dozen different character playstyle choices for a given element (except Water, but that was in the pipeline). And those are the types of "themes" I mean. Those are the sorts of powers I tend to build concepts around.
Heck, at one point I tried to just build a guy with a machine gun in CO (a pseudo Wolf Spider SoA), and I couldn't do it, because the Munitions powerset won't let you use just one gun for all the powers. You can't be a guy with a machine gun, you have to be a guy with two handguns, three different types of machine guns, a shotgun, a sniper rifle, and a bazooka.
"Learn to build better" only goes so far when the powers that fit a theme - or, at least, the themes I like to use - don't exist.