Should Microsoft add features in service packs?

This is an issue that gets debated around the company from time to time, and there are many people on both sides of the fence who feel passionately about it. In Exchange 2000 SP1, we did add a few features. In Exchange 2000 SP2, we added even more (I was the program manager for most of the new features in OWA in SP2). Exchange 2000 SP3 had -- read my lips -- “no new features” (also by that time, the entire team was heads-down working on Exchange 2003).

I have seen varying levels of feedback in Windows and Exchange communities on this issue, such as:

  1. “Yes“: It's OK for applications or operating systems to have features in SPs
  2. “No“: There should never be a feature in any SP of any Microsoft product, it makes the SP buggier
  3. “No“: There should never be a feature in any SP of any Microsoft product, even if the SP is high quality
  4. “It depends“: It's OK for applications to have features in their service packs, but operating systems shouldn't have features in SPs

I'm sure there are many more reasons, but one of the most common ones I've seen discussed is that the quality goes down whenever features are added (#2). With Exchange 2000 SP1 & 2, however, I feel we did a good job of adding features while still achieving a high level of quality, so ever since then I've been wondering if that has helped change any opinions about this issue.

(Site note: Several of us who participate in Exchange communities had a good time forwarding around the mail threads in those communities that happened soon after the E2K SP2 release that went something like this:

Person A: Knowing Microsoft's track record, what should I be aware of when going to Exchange 2000 SP2?
Person B: No problems here! Went without a hitch.
Person C: Likewise, installed it on 5 servers without a single problem. Users didn't even notice it.
Person D: Well, my users noticed it, but only because they noticed the new features in OWA and loved them!
Person E: Ditto.

...etc. OK I'll stop patting myself on the back here ;-)

Not that I mean to imply that no one had any problems at all, but the overall perception I got from looking through the support calls we got and seeing the chatter in the communities was that those SPs were well received, features and all.

So, all that being said, I would like to use this blog to hopefully start a conversation: In your opinion, is it acceptable for Microsoft (and the Exchange group in particular) to add features to service packs? I'm most interested in hearing why you feel the way you do, as well as whether you're talking about Exchange specifically, OS's or all products. Thanks in advance!