You don't count Blade Wolf as a boss? He'd have been a lot tougher if I didn't play him in the demo a bunch of times.
Yeah, if they made breaking Sundowner's more shields somewhat more necessary, I'd have bothered. It's the only time blade mode really annoyed me ever. Not like I didn't try - I did, at first - but I got tired of thinking I had it all lined up and, well, didn't. Other bosses were fine - dodging, parrying (for the most part etc).
Eh, the normal enemies were fine. The first Gekko and the first mastiff, etc. are always scary, but once you figure out how they work, I had little to no trouble with most of the regular enemies. Even when I had three Gekkos bearing down on me. But I also put WAY more b. points into the HF Blade than unique weapons for my first run.