Is it enough to tempt me from TS3?
No. I would rather play The Sims: Vacation and actually I've been meaning to re-install all of TS anyway. Too bad they never brought back volleyball. :(
Why does TS4 Island Living not tempt me from TS3?
Because it does nothing extensively better and is actually worse because of retrogression while having loading screens interrupt the immersion of gameplay than have one seamless huge play area. The game engine overall is nothing spectacular and is not on the same level in terms of improvement and advancements that TS3 game engine/TS3 Island Paradise introduced. Most features and content I have seen in the trailer are the same things already done before but this time around is just a weak version of it rather than improving and advancing over the old plus with brand new worthwhile features and content never been done before in the main PC series.
So no, I'm not impressed nor tempted. But off-topic, I've become impressed by Cyberpunk 2077 and now I hope that will be one of the few games I get day one besides Final Fantasy VIII:Remastered and Death Stranding. Oh and Pokemon Sword and Shield. Too many quality games that I actually care about and have proven to be worthy of my attention. Overall, TS4 Island Living can't hold a candle to TS3 Island Paradise.
So that's my honest thoughts and criticism. Delete it, leave it...I don't care. Do as you please.
