Curious about Island Paradise and Sunlit Tides and one other question

I already have Island Paradise (and love it, sans glitches :P), but I'd like to know if adding Sunlit Tides would be worth it -- how much it would change my current world, if at all? Are there any significant differences between them?

Also, I have a question about resort management. (Apologies if this is in another thread somewhere.) My Sim has purchased and made decent improvements to the previously run-down resort on the IP map (sorry, I can't remember the original name 🤭) I have three high-end maintenance workers tending to the buffet tables. They keep saying they have nowhere to walk (with the 'no footprints' thought bubble) -- they stomp their feet and yell, even though I have left plenty of room between tables for them to walk around; so much in fact that I have large bits of wasted space on the deck. So, is there anything I should be doing so they'll stop complaining, or are they just...dumb? I have two tiki torches beside one set of steps to the deck, both of which are well out of the way, but for some reason my employees want to walk through them, too! 😮 🤨