BL1: Extremely versatile special ability, gives utility for overland travel, a panic button, and an excellent tool for engaging and disengaging, which lays the groundwork for a skirmishing playstyle. The class bonuses are to SMGs and elemental effects, which tend to mesh well with that for obvious reasons: pop up, spray a burst, maybe fry their shields or set a DoT, then back off and reload. The skill trees primarily focus on improving the effectiveness of phasewalk, adding on-kill effects, and various buffs to damage and elemental effects which support the same hit-and-run playstyle. It creates a coherent functionality which gets some added perks in multiplayer.
BL2: Phaselock. Oh hey, it's that one biotic ability from Mass Effect. So... you can isolate a single enemy for a couple seconds? Great. Wonderful. Oh, and you can hurt it more. So, why? I mean, it's decent if you're dealing with a single boss with no adds (except for the ones it doesn't work on), but it's useless in most situations and doesn't really fit thematically. And what sort of playstyle do you build around "lock down one enemy for a couple seconds, except for a lot of the ones that you actually want to lock down"?. Do BL2 classes even get base bonuses? And then the skill trees, hoo boy. They're an incoherent mess of random buffs, many of which are highly conditional or only useful in multiplayer. The closest to an organized theme is the red tree's gathering of supplementary elemental damage procs, which might have been useful if so many of the enemy types weren't designed to be killed with a single damage type.
Thematically I recall hearing that the Sirens all have different powers. So, Lillith gets Phasewalk. Maya gets Phaselock. Maya's phaselock works more like a buff than anything else. With it active and the right skill points, you get increased damage, health regen, bullets ricochet, as well as the default ability of locking an enemy in place. So, it's a utility. Like Phasewalk. I honestly don't remember what Phasewalk did outside of entering/leaving battles.
I mean, when the closest I can find to a theme for the skills and ability are "Co-op healer and battlefield control" I sort of have to throw up my hands, because that's bloody stupid.
both sirens were about controlling the flow of battle though. Lillith with phasewalk could enter or leave the battle on demand. Maya can lock enemies in place, slag enemies, mind control enemies, various other tricks, all with her action skill and the right skill points, as well as passive tricks like reflecting bullets or inflicting damage equal to damage you take. So, yeah, siren=control the battle. Sounds like a theme.
The plot actually really bugged me. BL1 had a plot that was what it needed to be: an excuse for murderhobos to wander around collecting guns and shooting things. Not to mention the way they shoehorned in the original cast and subsequently overshadowed the player by making everything about the conflict between the BL1 PCs and Handsome Jack, with the player there only incidentally. That's just bad writing; the PC feels redundant and unnecessary, which is only made worse by them being largely less interesting (IMO, of course). The game is saved by all of the wonderful side characters, though, and by replacing Claptrap with literally anyone else.
This is actually a really good point I never realized. You're right, the PC does feel shoehorned in. I guess it can be kinda excused with "you're a part of a bigger plan, there's wider scale events on pandora than BL1, blah blah blah" but it does feel like the BL1 heroes steal the spotlight. Then again, do the BL1 characters do anything in their game besides run other people's errands while they revolt against Atlas?
Heck, even the trash mobs are more annoying. Stalkers. Fuck stalkers so much. And where are the human enemies? I've played for hours and maybe 3% of what I've fought has been human, and probably >50% has been robots. Robots with boring lines, boring behavior, and boring ways of being dealt with.
Enemy AI can be annoying yeah. Stalkers going invisible is annoying. Loaders are annoying as hell to fight. The little flying drones that repair enemies are a huge pain in the ass to kill as a melee character -read: Krieg- and especially when they're the only enemy left but you have to kill them to progress.
Stalkers are really flimsy and can't go invis without their shield though. Destroy the shield, bam, easier to kill.
Loaders can literally be dissected by shooting limbs off. That's a neat mechanic and I loved finding that out during my first playthrough.
The little drone thingies can be drawn in by damaging a loader enough to request repairs. So there's a strategy to make it easier to kill. So it's not like it's completely broken or stupid, just somewhat inconvenient. It requires more thinking than just "shoot everything" though. enemies seem relatively balanced in regards to how they're annoying. They're annoying, but you can do something about it.
The things that cheesed me off the most were the scaling in BL2, the way combat became complete rock-paper-scissors with maybe two or three enemy types, each of which requires a specific elemental type to do anything approaching reasonable damage (fuck those robots, they almost ruined the game alone -- not only are they everywhere, but corrosive is the least interesting elemental type),
The rock-paper-scissor element game was in the first game as well though. Shock for shields, fire for flesh, heck, corrosive even played the part of slag by making enemies weaker to damage. The biggest difference between 1 and 2 as far as the element metagame is is the scaling in BL2 breaks it and makes it almost essential to do damage. Don't blame the elements metagame, blame the scaling. Also, Torgue explosions master race.
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This conversation is making me want to play BL1 again. Shame I lost my Xbox copy.