Yes but those players injected into the Richmond side certainly did make us contenders to the tune of ultimately 3 flags. So it's the nature of the side and where it's at on the premiership clock, what players are required and the crucial contribution they could make - all quite transparent with Nank, Prestia and Lynch.
Everyone is entitled to their opinion - you or me included - and for me, although Mitchell might collect a lot of possessions, I greatly prefer a player who has far more hurt factor with his disposal. I'd rather encourage our young mids to develop into the best players they can be through greater opportunities now as Cotch, Edwards, Riewoldt show clear signs of aging, and perhaps Prestia/Martin/Lynch also diminish in potency due to injury setbacks.
I really doubt the addition of TM will make such an impact to compensate. We need to plan ahead for the decline and loss of our champion players now rather than throw away vital early draft picks for an accomplished player but one with their prime years behind them.