the only time I ever made big early changes like that was when, thru oversight, I realized I was deficient in some aspect to match up against my division. I've learned and now spend a lot more time post waivers making sure I have a decent mix. as marc said spend that 4 million wisely and take your shot. ss and sp seem to me to be the obvious places to improve.
case in point on patience I was whining in another thread about my 1st 2016 team, stuck in a glitched 20% drop penalty league, being 15-22 with no hope to be righted. well I made no changes, except lineup and pitching adjustments, and have since gone 27-11. I am finally in the wild card spot and am 30 runs ahead of the 2nd best team in run diff. in a 5% league I probably would have ruined my team.
http://365.strat-o-matic.com/team/1423316