Battlezone II could have learned much from its predecessor as well as the other way around.
First off the story line was good but the missions were far too linear to hold up against the previous installment in the series. Rather then you deciding what to do and how to do it in the order you want the game forces you to do things in order, also while you may be able to get a good base going you'll many times have to abandon it to go on a solo crusade.
The ai is also lack luster at best because they have no "thought" involved in thier movements, for example if I tell a team of mortar bikes to attack an enemy base while I go do my solo thing and there is a canyon riddled with defenses between them and the base, they won't stop and fight the defenses, they'll zoom right by and most likely get completely destroyed in the process due to the power of the defensive towers.
The units and weapons themselves also lost a lot from the predecessor for instance howitzers bieng replaced by mortar bikes on the ISDF side of the fight, mortar bikes are flimsy and often hard to hold at an exact point to do an accurate bombardment of a tower or base, the Archers on the scion side are a much different story as they are basically flying howitzers, however you can't pilot them only the ai can.
How the weapons are put in the ships was one of the biggest issues I had with this game. In the original battlezone ships were VERY customizable as far as weapons went, you had cannons, rockets, and specials. Sounds very basic but that arrangement allowed you to take a scout and put much better weapons in it, then make yourself an ammo dump that you could retreat back to since the larger weapon consumed so much more ammo. In this installment what you can put where is much more limited since you have cannons, guns, rockets, missiles, specials, shields and all of them can only go in thier specific slots. A more detailed example would be that the scout unit in the first battlezone had two cannon slots and a rocket slot, almost all the same weapons existed but since there were only three categories I could customize it so much more, for example I could put a comet cruise rocket in that slot on a scout, wheras on BZII the best you can put there is a tag cannon.
Ship design in BZII bothered me as well, while the tanks admittedly looked good (at least to me) other ships looked like scrap, ISDF scouts for instance looked terrible, while the fins on the back were good the front just looked like junk. the walkers were none too good either everything else was o.k. but not great, while the scion side looked much better for the most part it still wasn't great.
Placing buildings was also much less free because rather then bieng able to place them wherever you wanted the terrian was shoved into a giant grid so it felt much more constrained, also the fact that ISDF bases had to be shoved together often made them crowded and hard for the AI to navigate, more then once I found myself stringing power plants together just to get a little open space between the bigger buildings in my base.
Some noted improvements however were things like Scrap Pools, in multiplayer they made excellent conflict points. also the fact that you could upgrade the scavengers on them to make them more efficient was good if you (like me) preferred it to be a little faster.
Control of units was much nicer as well aside from the above noted AI issues. More options as well as a VERY nice satellite command view made things much easier. I often just hopped into a relay bunker to build my base and control units to specific locations before going out in the field myself to get some very coordinated attacks.
The multiplayer was also very good strategy is my favorite but admittedly some of the deathmatches were very good as well.