Hello there! I have a fair amount of experience with both an ESP Horizon NTII (Nailbomb set, regular-thin maple neckthrough tuneomatic) and an ESP Edwards AL 120 (Holydiver bridge, very thick maple neckthrough floyd rose). I seem to have different experiences from what you describe. I find maple has this very rapid quality to the frequencies that it delivers. It's not just the bass that is tight, but all frequencies come at you rather quickly, there are plenty of all frequencies, and it has an emphasis in the upper mids by giving a scratchy attack to the notes. This rapid frequency response and scratchy attack is what I would say really helps give the archetype ESP metal guitar sound that so many bands use. Downtuning will help reduce the brightness of the attack and loosen the bass but those tonal qualities will remain.
However, one thing to note is that the thicker the maple neck the more bright and bassy the guitar will be, and exponentially! One issue I had with my Edwards was that it is so damn bright AND bassy. I have tried a Painkiller in it, an Abomb, the original EMG HZ H4 in it, a SD Full Shred and finally the Holydiver. The pickups that work well with it really seem to have a controlled high end (Full shred and HD). The PK and EMG just had way too much attack and high end frequencies for it. One pickup that absolutely rules in the Edwards is the Holydiver. That is a match made in heaven (like waffles and maple syrup..... I had to do a bad maple joke) because the guitar has a huge amount of natural bass and tightness to it, and the HD just lets it sing and chug, while at the same time really helps control those upper mid and high end frequencies. The guitar rules at heavy metal and death metal, and really does well on cleans for a bridge pup. If the neck is thick, then I would suggest sticking to A5 magnets for metal, but if the neck is thinner/regular than I'm sure you can use ceramic pickups like the MM. In comparison, the Horizon is really much darker - it has a good chunk of tight bass but it is nowhere near as bright, especially when you let power chords roar, and has less bass, but it keeps a lot of that scratchy maple attack. Also, the Nailbombs just does not seem to like non-thick maple neck through guitars, and they will always emphasize the guitar's attack whether the neck is thick or thin. They work, but its not one of those great matches like with mahogany. From my experience with these two maple neck guitars, I think if you tried the Alnico blackhawk, A-Pig, or the Holydiver (in E, E flat, or D tuning) you should be a really happy camper. And have no fear, you won't get lost in the mix with a maple neckthrough, ever.
