As the 'default' rules stand, placing a Quint (5 of the same) or an Ouroboros entitles you to play again. With a one-tile (small) hand, making a strategic play with only one tile is functionally impossible.
Optionally, one could draw a second tile before placing the Quint or Ouroboros, but that seems clunky, and reduces one's time to plot or anticipate.
A two-tile (small) hand solves that problem, and introduces a modicum of strategy for all moves by giving more options for scoring potential, and increases the penalty for loss (by roughly doubling the unspent pips in hand).
I think a three-tile hand is too large, but I haven't had a chance to gauge the two-tile hand yet, let alone three, so that is where it is at now.