I binged the whole Millennium Wolves series over the summer, and honestly, the ending left me with a weird cocktail of feelings. On one hand, the main couple's arc gets a definitive, romantic closure that really leans into the fated-mate trope the series is built on. It's a proper HEA, with all the pack politics settled and the big bad defeated. But the sheer number of side characters and spin-off bait by the end kinda diluted the impact for me. It felt like the author was already building the extended universe while wrapping up the core story, so the final chapters had this split focus between giving Sienna and Dominic their moment and setting up like, three other couples. The emotional payoff for our mains is there, but you have to wade through a lot of other stuff to fully savor it. I still reread their final scene in the last book because it's genuinely sweet, but I skip the epilogues that are all about new side plots.
If you're in it purely for the central romance, you'll probably be satisfied. If you got invested in the world itself and wanted every thread tied up neatly, it might feel a bit messy. I've seen some readers argue the series actually ended a book earlier for them, with 'Alpha's Temptation', and everything after was bonus material. I don't agree completely, but I get where they're coming from.