If you record a VCV, you don't necessarily have to do it w/ a guide bgm, although you still wanna keep the general tempo. Then, you can use set param's auto generator and either edit it in set param or adjust it in utau itself.
Moresampler definitely cuts off too early and doesn't give you as much transitioning room and it's v non uniform and some people will try to say an edited VCV oto is better than a uniform one (although, there's a lack of evidence supporting this because it's a VCV oto, not a CV one and the transitions are natural so you don't need to mess with the overlap). I mean if it NEEDS to be edited so there's enough room and so that the green line remains on the vowel and red line inbetween the consonant vowel (or, in front of the pure vowel), then editing is ok for those samples, but, a uniform oto will sound very smooth vs an edited one.
I'd say right now, moresampler is excellent for testing out a voicebank you just recorded so you know how it'll sound, but not for a release.