Fundamentally disagree that there is no edge. 1) If you have 90 players (which is only one scenario here) it creates a mess for teams dealing with arb for you. Yes, 60-70 of those guys are probably easily ignored, but I still have to sort through 90 players to deal with arb for your team. This increases the likelihood that players sneak through/bad choices get made. 2) some of those random prospects are the guys who are going to break out in winter leagues or pop up on a couple top 100 lists unexpectedly and see their value increase. If you want to make a smart bet on a handful of guys with solid A-ball numbers and hope that, within your 40+60 day DL slots roster spots you hit it big, that is totally fine. but sitting on 90 guys gives an out-sized shot to hit on one of those guys. 3) the more common scenario I see is bidding up the few reasonable pieces still out there (for example, across my leagues, in the last week, Stanton, Heyward, Yordano, Felix, Upton and others were all cut) and sitting at maybe only 4-5 guys but $40-$50 over the cap. All those extra players can be used in trades, etc.
On top of this, even if the advantage is small, there is a bit of a tragedy of the commons thing here. Sure, having 11 rosters at 40-45 players and one at 90 is not the worst, but the incentive is now for every owner to do that, which means come 10/15, when arb starts, there are now 1000 players owned across each league, instead of 480-500. That is a huge difference. and it will make the off-season suck. I have no interest in dealing with a roster that big, combing through rosters for arb/trade talks, or getting an offer like, "I'll trade you X for Y and I'll even throw in any 20 of these 40 shitty players that should not be owned but are."
In season, there is already a penalty - being unable to make trades, claim players, or bid in auctions is a real problem. But come the last day of the season, I can put in my bids and claims, sit back and suffer no penalties, then go into the off-season with a painfully overloaded roster. that is not right.