IMHO, there's a fine line between "features" and improvements required to keep ZP going. Adding a slideshow or ordering prints would, to me, be a feature. Not necessary to the functioning of ZP but something some want, others don't (I'm latter). Improvements are what keeps ZP running smoothly and applying new knowledge/techniques that don't hinder it's operation.
I'm on dial-up and also found Gallery too bloated and complex to handle. There was no way I'd do a self-install! (Dreamhost use to offer the install). ZP, I skipped Dreamhost's offer to install and download the nightly builds to the main install I have. Easy, compact, and doesn't crawl on 56k modem. (All images were already optimized web display)