Fomalhaut writes, "Is coming under the gun to challenge the blot on the 15pt compulsory, or reckless?) Also, aren't split & slot plays—especially ones so diversified for your opponent as this—one of the cardinal sins of backgammon?"
If you are worried about "coming under the gun," it sounds like you have been reading Magriel's BACKGAMMON, published in 1976. Although splitting into the face of three builders carries some risk, it is frequently correct when your opponent has only a one-point board. It can also be correct even when your opponent's board is stronger. It is sometimes necessary to split into the face of four or even five builders.
This was a fantastic book when it came out, and I would still recommend it to someone just starting to learn backgammon. However, opening theory has progressed a lot in the last 35 years. To start getting up to date on opening theory, I suggest Backgammon Openings by Nack Ballard (and some unknown coauthor), which can be ordered at www.nackbg.com.
I will make a few comments about 63S-32W after the diagram below.
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 on roll, cube action? | ||||||||||||||||
is Player 1 eXtreme Gammon Version: 1.20
This is one of the most interesting second roll positions. Four plays are essentially tied and four more are not so far behind.
After Black's 63, White's 32 is a lousy number, making him a distinct underdog in the position. By playing W (Wild, 24/21 6/4), White duplicates Black's 6s (24/18 and 10/4*) and 3s (24/21* and 13/10). Although it is certainly true that W gives Black some strong hitting numbers, all other plays with 32 also give Black some very strong numbers.
W tries to make something happen on both sides of the board: it attempts to make an anchor on Black's side and a strong inner point on White's side. White has a decent chance of making one or the other, but sometimes he will make neither or both.
Hope this helps.