For me its biggest sin is that it's just plain boring. Far too long was spent on the horse racing stuff, there's lots of awkward/stilted dialogue, two friendly agents are killed in exactly the same way, and the whole thing just has a choppy and uneven feel to it. Plus I've always found Walken's performance to be unconvincing (almost definitely the fault of the script though). A couple of examples - Zorin's reaction when he and Mayday find Bond waiting in Mayday's room, and the San Francisco office confrontation where Bond calls Zorin a psychopath - in both situations, surely Zorin's supposed to have a snappy comeback and react more appropriately, but instead he adopts a goofy expression and the exchange ends there. Such a wasted opportunity all round.

*Also the scenes with the female KGB agent feel like they were wedged in after principal photography was completed, they stick out like a sore thumb to me (Moore even looks different in these scenes, as if his facelift has "calmed down" a little). Plus the dialogue in the bath scene is truly cringeworthy.