No, definitely not, as training pokemon at low levels was and has always been incredibly easy, lucky egg can already be obtained through the ability pick up and when I got another one through the story line I felt ripped off of all my hard work with that. On top of that lucky egg has always been obtainable, so it's not like it has been added to compensate for the lack of experience later... If they had of had the foresight to put in trainers with higher level pokemon, then maybe it could work, but as it is, the cons of taking longer to reach level 100 outweighs the benefit of quicker earlier training.
My advice is carry around 5 level 41+ Lillipups with Pick Up ability (plus the pokemon you're training). This is because from level 41 upwards Lillipup has the best chance of holding a rare candy after battle, for a few free levels. As well as using your main pokemon holding a lucky egg. Then use the rare candies for the last couple of levels, don't waste them on the incredibly easy (and always have been!!) low level pokemon.
Oh and on a side note, I gave up on using a team of pokemon in this game... there wasn't enough exp when the wild pokemons levels became too far below the trainers... so I switched to just using Emboar and breezed through. Though I had to use 10 rare candies (from my Lillipups before I beat the E4... making it level 74...)