In most genres of computer games, you usually see one huge, ultra-hyped release of a game followed by a couple of bug-fixing patches and then silence for a year or so as the next version is in development.
For a typical Roguelike game, however, you tend to see many small updates per year, sometimes several per month. Additionally, when a Roguelike game is open source and is enjoying a decent amount of popularity, you'll often see a lot of variants popping up from it.
Right now [Feb99], Angband is the "hot" branch. Even though "vanilla" Angband itself hasn't been updated since Feb98 (a year ago), several of Angband's older descendents (e.g., Zangband, Kamband, AngbandTk) are enjoying frequent updates. New Angband variants are appearing at a rate of around one a month.
Meanwhile, most of the other well-known games have been pretty quiet recently. NetHack's most popular variant, SLASH'EM, hasn't been updated since Dec98. Nothing's stirred on the ADOM front since a pre-release version in Nov98. Omega hasn't been touched since 1995 or 1996, although there's an increasing demand for its resurrection, so we might see it roaring back into life any day now...
Of the newer Roguelikes, Crawl is currently getting the most attention, from both its developer and from Roguelike gamers. Someone remarked recently that on rec.games.roguelike.misc, all but 4 of the hundreds of recent threads pertained to Crawl.
Well-publicized updates serve as reminders, enticements (new features, bug fixes), and implications of commitment to future development. The more frequent and better publicized the updates, the more effectively an audience is obtained and retained.
It could be that commercial gaming companies have reached the same conclusion. Free advertisement provided by patch releases could be contributing to the growing number of [relatively minor] patches we see compared to ten years ago. Of course, relative increases in game complexity and competitive pressure are big factors as well, but it's becoming easier and easier to wax cynical and conclude that commercial gaming companies are unconsciously [or even consciously] motivated towards making incomplete releases. Anything to keep your name in the spotlight...
Popularity and feedback in turn inspire further development. Bug reports, wish lists, criticisms, and player-code patches all serve to energize development.
However, before you go flooding your favorite [or least favorite] developer with email, you should realize that every developer has a feedback threshold. Too many suggestions, too many backseat drivers, too many expectations to meet, too many hands pulling the pencil in too many directions... Too much feedback can end up intimidating an artist rather than inspiring him.
If you do have comments or questions for a developer, I suggest you first send him a feeler email so you can get a sense for how busy he is and how receptive he is to feedback at this time. Remember, Roguelike developers tend to work individually and have day jobs and classes like the rest of us. Every hour they spend in development is an hour they don't spent hiking, biking, skiing, watching TV, or spending time with their girlfriends.
Aside from the long term, evolutionary effects mentioned above, one must also consider the immediate impact that the pace of Roguelike development has on the player...
On the one hand, rapidly changing versions makes it difficult for an experienced Roguelike player to choose the right time to commit. We have learned the hard way that it is frustrating to download a game and start up a cool character in it, and then a day later a new version is released which fixes bugs, adds neat features, but won't work with your old save file.
Even the act of installing a new version over the old version is a pain, as it frequently has side effects that require you to: reset your options, reposition your windows, reconfigure your personalized help system, and kiss your old high score lists, monster memories, and macro definitions goodbye.
On the other hand, who really wants to complain about not having to wait forever [sometimes literally] for bug fixes and cool new features? Who wants to halt the progress of Roguelike game development in the name of installation convenience (which could be an entirely platform-dependent concern)? And even when versions labeled "Beta" and "Gamma" come out, with clear warnings as to their potential instability and the inevitable patches to come, who among us can actually resist snatching them up as soon as they appear? Certainly not I!
I only wish there were a way to make upgrading less painful. I would very much like to be able to download a patch and know that it won't require any reconfiguration on my part. However, Plug-n-Play seamlessness takes time and could sap motivation; I'd rather that developers spend their time worrying about bug fixes and cool new features than worrying about the installation utility.
Maybe some kind and energetic fans (or developers themselves) out there will be able to come up with a way to minimize reinstallation side effects. That would be a huge boon to the player and an excellent topic in itself.