This is a good point, and is relevant to other classes such as rogues, or even healers (although few people will complain about having too much healing) when there is another one present. About the only classes that are free from this are truly versatile classes, and classes that can put down massive dps. (Nobody ever complains about too much dps either!
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ED's opened up opportunities for some of the damage shortcomings. The reason I always build my bards for healing is because no one complains about an adequate healer with a DPS buff and CC when needed.
But to go back to the bard, this is the issue. The bard isn't really great at anything, and any backup abilities aren't exactly going to impress anyone either. (Not counting the occasional "wow, I never knew a bard could do that!" There are advantages to having rather low expectations thrust upon you sometimes) Let's look at another class that is versatile and unique... the druid. The druid can melee about as well as a bard, or focus on melee and be pretty fun, if not impressive. The druid can heal as well as a bard, and far better if specced for it. The druid can CC far better than a bard at higher levels. And on top of all that, the druid has offensive spell casting abilities that a bard does not have. And that's just the tip of the iceberg.
Druids have no wand and scroll enhancements, and they use AoE HoT's instead of AoE bursts. A bard can burst heal a group with MCMW and MCLW plus gets up to 75% wand&scroll. Druid shape changing also interferes with scroll healing, which is a big part of the game in many places. Bards also get +80 positive spells power in the enhancements compared to the druid's +65. They are more similar in terms of healing capabilities than you might realize.
Also, druids have some decent spells for CC. Earthquake is awesome. Snowslide is fun. Their spells don't have the durations that something like disco ball does, and they don't have the debuffing prep spells to go with them, let alone the ability to match DC's on the fascinate lines. The spells are nice but I still wouldn't consider them on par. CC is something bards really can shine at. Unfortunately CC is still a situational need most of the time.
Yes, the bard is the classic jack of all trades. In a game of min/max effectiveness. It wouldn't take much to fix, but I'm afraid it'll never happen, not the least of which is because of the box that the druid has been put into. He's a raid buffbot, a hagglebot, and a little like the ******** kid that used to live next door. You let him play with you because you felt bad if you excluded him.
It's time to think out of the box for the bard class. Luckily, there is multiclassing, because I'm afraid that's the only real tool we'll ever have. The enhancement update might fix a couple of things, (like removing required feats for pres on a terribly feat starved class, or updating/completing the pres) but I will wait until I see the update. I'm hopefully optimistic that the bard gets a bone, but deep down I'm a realist.