Yeah, I've had issues with this in past basketball games as well, including 2K's NBA 2K11 game.  I didn't have the heart to pick up last year's game, given how badly-composed my team was last year at the start of the season.

I follow basketball pretty consistently during the season, so although I couldn't lay out play diagrams for you, I can generally tell you what kind of plays to run depending on the situation.

For example, just looking at your second paragraph the baseline is the area that runs along the edge of the court underneath the basket.  A common tactic my Jazz always used to run in the Jerry Sloan era was to have a Point Guard with the ball run along the baseline to fake the interior defenders into thinking they were going with a lay-up, only to pass the ball out to an open shooter lying in wait on the other side of the basket (who would then either take the shot or pass the ball to an even more open shooter on the other side of the half-court).  This draws the defenders off the shooters for mid-range or 3 point shots.  My Jazz also used to run this play using the PG to draw attention off our PF, who would be charging through the lane.  Then the PG throws the ball to the charging PF, and the player has a reasonably uncontested lay-up or dunk.

As for a 2-3 Zone, I'm not entirely sure of the details, but defending teams call for Zone plays when they know the opposing team relies on an inside game and don't have shooters on the floor.  I believe a 2-3 Zone calls for 3 defenders standing in or around the paint to prevent any opposing player from going in for a dunk or layup.  IIRC, the other 2 defenders stand between the 3 point line and the paint to attempt to block players slashing from the Wings past the 3 main defenders.  You're essentially daring the offensive team to shoot jump shots, and generally teams will run Zones until the offensive team either puts in a speedy player who can run around the defenders or a shooter who can rain down 3 pointers from the Wings.  At that point, the defenders usually resume Man-to-Man defense, where each defender strictly guards their offensive counterpart.

Unfortunately, my Jazz being traditionally very dunk and layup-oriented, teams just love to go to a Zone when we're having a bad shooting night.  :-\

I highly suggest picking a team you like and learning their signature plays in the Training mode.  For instance, my Jazz tend to rely on Pick & Rolls and cutting from the baseline as I described, so if I wanted to get good at the game I'd practice those plays until I knew where players would be and when during a play.

As a huge fan of basketball (nba 2k) and football (nfl 2k but madden by default ATM) I can see how things have become difficult.  I too have been one to never really run plays during my time with these games but its becoming more apparent that in order to really succeed, you need to at least run a couple of plays.  This is evident when you play the high ranked teams or teams with high defence.  Its even more important when you play competitively online against really good players. 

I have yet embraced this technical approach but am slowing changing.  The most I do at the moment is adjust my defensive schemes on defence and live off of the pick and roll and post games on offence.  Also, listen to everything Broodwars posted above me.  Without running plays, you can live off pick and rolls and moving the ball around.  Defence always depends on whats hurting you, in a nutshell, zone for attackers and man for shooters.

I do recommend starting on easy though when you jump back in.  You might struggle at first but once you get the hang of things, you'll be killing the CPU and eventually adjusting the settings.  Also, refrain from playing reckless and be patient.  A commom approach to new gamers raised on the oldschool basketball sims, especially live, is to just want to jam the ball into the paint with an arrey of slick ball moves and then dunk it on the opposition.  That's just not going to work.  You'll more thank likely get the ball stolen or have a charge foul called on you.  Also, be very careful with your passes, don't try a fast brake unless your sure you can pull it off and the same goes with an alley-oop.  Basically, just be very patient and pick your spots, don't be afraid to live off the jumper.  Once you've mastered the pick and roll, you can then start getting comfortable with attacking the rim. 

Good Read. I buy NBA 2K ever year. have so far for this past generation. Stated off on the 360 and now on the ps3. I loved jam, and live back on the GC. Even though i always though courtside was better. IMO. NBA 2K13 should be launch title for WII U and its a definite day one for me.