Modifying the Chit draw system to the Pleva system would be painless. It simply is reminiscent of the number of Missions in the 4 chits of the SL system...you are GOING to get at least 1.
Not always. Its possible to draw red after red. It is exceedingly rare though. Less rare if you have a shallow deck (5B2R becomes 5B3R becomes 5B4R etc).
The POBA system is good although it does introduce a slight shift to the right on number of FFE:X you place. It is not huge, but it happens enough it skews the average by about 2/10. It also messes with extra chits draws once you've pulled the first red. Again, not a big deal. I would be all for it if there weren't a better (IMO) alternative system. The extra red card also hits shallow decks harder than deeper decks (think 5B2R becoming 5B3R vs 10B2R becoming 10B3R).
@STAVKA's system introduced in his Leaflet House Rules is a better system IMO. While Melvin and I disagree on the minimum number of guaranteed SR to FFE conversions, which ever guarantee you chose to live by is mathematically sound when compared to the base system. Whether you use the one or two minimum, it pushes the zero and one FFE's into the left-most column almost exclusively. It also never messes with extra chit draws. The one minimum system is mathematically equivalent to "First card draw is black" SSRs.
The thing you have to ask yourself is should OBA always be a threat? The POBA believe it should be so it never goes away. Melvin's system doesn't so it can go away. Both systems guard against 2 reds being no OBA. Both systems guard against breaking the radio. Both have an improved repair number. Personally, I think if a player wants OBA to always be a threat in being, they should not convert the SR to an FFE. As such, I prefer Melvin's system and it is what I use when playing my games (although I only use 1 guaranteed mission, not 2 as Melvin does). I think it remains truer to the original system than POBA. Just my .02. -- jim