I'm not exactly bored with the Sims 4 but I don't play for as long as I once did. I understand in some ways how the OP Cinebar feels.
I lose direction and inspiration in the Sims 4 game. The reason is the Sims 4 feels disjointed to me. The order in which expansion packs and other items added into the game have not been in the right order (imoa). Packs should build on a Sims Lifetime, instead things like University have been left till quite late in the game. One of the things I enjoyed was taking a newly created YA in the Sims 2 to University to achieve, come out with lots of skills, friends etc. With Discover University in the Sims 4 the experience doesn't seem the same as it was in the Sims 2. I miss the mischievous Mascots coming into the dorms/community lots, being able to take my Sim on a vacation while still at university once they had achieved all their college work and of course finding and going to the secret society and all the advantages that it brought. I haven't found the secret society in the Sims 4, my Sim barely had time to do anything but college work lol.
I miss things like slow dancing and other special interactions with a special sim; making a band and asking others on the lot to join in playing no matter what their skill. Yes it sounded awful at times but that was half the fun lol.
I love the Seasons in the Sims 4 although it messes up so much with growing plants, fishing and exploring places like Outdoor Retreat especially in the Winter. I love the flower arranging but disappointing that fresh flowers soon wither and die. I thought this would be good for making a flower shop and selling but when they don't keep fresh the options seem limited. The same with fish going off once caught and left in a the Sim's inventory. Sometimes reality is not so good for creating game play the way the person wants to be inspired and create in their own game. Perhaps they should have given the Fishing skill when maxed out a way to keep the fish fresh and the same with the flowers arranging.
For me the Sims 4 also lacks character and by that I mean there seems to be very few special NPC's. Mrs Crumplebottom (in the Sims 2) with her prim ways and hitting Sims with her handbag lol. I used to get annoyed at times with so much fighting going on in the Sims 2 with NPC's on community lots, but the NPC's in the Sims 4 seem characterless. They arrive at a community lot, don't stay very long and even when one of them comes to speak with my playing Sim, unless my playing Sims stops what they are doing and introduces themselves they get no friendship status with that NPC.
I think the video sessions in the Sims 2 also added to the fun with achieving things like first kiss, graduating at Uni, woohoo in a hot tub. All added to making it a bit special and fun to play those aspects.
I will continue to play the Sims perhaps not as much as I once did.