After a few hours of game play,
I think one thing GSB did much better over GTB is the situation specific map couple with the troops’ visibility.
In GSB there are certain maps (If I remember correctly back in 2010) are in favour of certain technologies and enemy units are visible for us to plan ahead.
I think this is where GTB lacking… despite some multiple paths, maps are general and do not know the enemies like "fighting in the dark"someone mention.
consider giving map more influence? i.e - high land for wider defense range bonus, also favor attack infantry but not vehicles. Jungle maps may have some cash-able destructible bush / trees favor vehicles but not infantry. Hazy(fog of war), Swampy areas, etc This kind of map create strategic dept in planning just like GSB.
As some one suggested: either base production or Attacker vs Attacker mode that mirror GSB. we can add that with fixed amount of troop or tower informed ahead thru “radar scanning” for defender and “Intel map” for attacker witch allow them to deploy random attack in any point of the map before the strategic point.