My initial review in 2010 was a bit harsh (below). But GW swiftly pulled the plug on supporting the rules shortly thereafter.
WAB2 solved a lot of problems for tournament gamers, stitched together the varying books were running their own systems for Medieval and some periods, and streamlined some rules that were funky leftovers from the WFB rules (such as lapping around).
Unfortunately by adjusting the unit point calculations they ruined all their previous books and that meant the system would not be complete until those were all revised. The WAB2 Armies of Antiquity volume did overhaul almost all the detailed lists from all the historical supplements into an immense compendium.
Some of the rules changes were simply liked/hated as a matter of taste. A major change was making the rank bonus for units four models deep redundant. This changed the visual impact of the game by allowing more three deep formations to balloon up in importance. I preferred that four deep units be rewarded so massed unit like warbands and pike phalanxes would retain that visual spectacle, but that evaporated and folks rebased.
Some of the other nuances that caused some grief were inexplicable changes to rules like Stubborn- which instead of simple being fixed in context with other psychology rules was reinvented an thus caused other newly unintended issues.
Things like this are why many folks prefer the WAB1 or WAB1.5 for their home games, because they can use the supplements.
Tournaments today often go with WAB2 because the lists are using the same points systems. Usually the old standard points systems in WAB1 for an evening sized game was 2000 pts.
Using the same sized forces for WAB2 usually was expanded to 2800 pts.
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A cheat sheet for WAB2 charts helps keep rules separated in one's mind from WAB1:
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