yeah i wouldnt waste time on loops. Its probably more time consuming to cut it to exactly the right point so that when you connect it to the next one it syncs perfectly(which it has to) than it is to just play the track over again, at least for me it would be. Then theres punch-ins. I think in any decent recording program you should be able to select the part you screwed up, punch it in and then hit record again and only the part you want to redo is recorded over again. Try to make sure your volume levels havent changed.
From an asthetic standpoint loops will always sound sort of fake because the little imperfections dont change throughout the song.
