Well, I'd look into the models one step below, which would be the PSR-E363, which has 61 keys, and the PSR-EW300, which has 76 keys. Other than the number of keys/octaves, I believe the functions of these keyboards are identical. By the way, do not confuse the PSR-E363 with the PSR-E360 -- they are completely different keyboards, with the E360 being a far more basic keyboard.
The E363 and EW300 still include hundreds of voices and the ability to split and layer sounds, but I only got that from Yamaha's website. I don't have much first hand experience with either keyboard, so you'll want to check them out in person. For example, while split and layering (dual voice) are possible, I don't know if you can change the octave or volume of each voice independently. And I seriously doubt there are any of the editing features, like the filter and envelope generator. But if you're looking for a keyboard that still has a lot of sound variety but without all of the complexity of the E400 series, then these may be worth a look.
One other thing to keep in mind... While the E463 and EW410 allow for 32 registrations (memories where you can store your favorite sound and style combinations for instant recall), the E363 and EW300 only have 9 registrations. That may not be a big deal if you're just looking for something basic to play. But if you start learning to play a lot of songs and want to quickly change instrumentation during a song, the more registrations, the better. It's almost impossible to manually change voice numbers -- and especially to also change split, dual, reverb, and chorus settings -- quickly enough while playing a song. You might want to change voices like this, for example, when going from a verse to a chorus of a song, and often there is only a fraction of a second of time between the last notes of a verse and the first notes of a chorus. This is where registrations really come in handy.
