Yeah, I have a feeling most presentation tools (Keynote, Impress, Google Presentation, etc.) would work well for this. In fact the only pain point I've ever had was the occasional desire to change the slide size. I've found that most of the basic effects in PP have a CSS equivalent as well, a surprising number of the things mocked up in PP can be recreated entirely in CSS without images.
Most of the actual graphics I use in the mockup I've made in Photoshop anyways, and just put them in the mockup, so those are reusable art assets on the final page.
(plus you can even mockup smaller gui details like drop-down menus if you are clever enough, though it's usually more work than it's worth)
I've found that most of the MS-Office tools can be abused to do a pretty good job in roles far removed from their original intent.
Most of the actual graphics I use in the mockup I've made in Photoshop anyways, and just put them in the mockup, so those are reusable art assets on the final page.
(plus you can even mockup smaller gui details like drop-down menus if you are clever enough, though it's usually more work than it's worth)
I've found that most of the MS-Office tools can be abused to do a pretty good job in roles far removed from their original intent.