HW 2 frigates are referred to as "Glass Cannons" for a reason. They pack a punch, but 2 shots from an Ion, or Torpedo Frigate, and they are finished, and Destroyers can wipe out whole squads with ease. In HW 2 frigates were cheap, easily replaceable, cannon fodder.
In HW 1 the Frigates were much tougher, and losing one would hurt. The expense, and build times also made you take care of your frigates, because replacements did not come easy.
Strike craft play totally different too. HW2 the strike craft are in squads. In HW1 the strike craft are single units. HW 1 strike craft use fuel which is all part of the strategy of the game. Especially vs the Kadeshi.
HW1 uses a physics, ballistics, and trajectory system for its weapons Where HW2 is a basic D&D style die roll "hit, or miss" system. As far as combat goes the HW1 engine is far superior than the HW2 engine. If anything HW2 should have been ported to HW1 then a shiny coat of paint put on.