So I went back and tried again.
I was dead within seconds. Never even survived long enough to do the first melee. I was killed by his charge against my cover and it took me out.
So I went back and tried again.
I survived the charge against my cover and tried to melee. Liara did her magic and he promptly died. Go figure.
The whole scene was a complete waste of time and nothing but an irritant.
You're not supposed to stay in the same cover all the time (unless you kill him fast enough). If he charges, you run.
Are you pllaying on Insanity? If so you do know that unlike in ME3 you don't have to beat the DLC missions like this one and Overlord and Arrival (those are literally post game content) to be awarded the Insanity trophy because you can continue playing after the final mission (Collector Base Assault) unlike ME3.
The only issues I have with this comtent is that there are barely consequences from it in game: killing a Spectre doesn't make the Council call on you to testify leading with a second encountee with A/K.
Your class can make a huge difference in how difficult, along with how you have spec'd Liara.
I have only played this fight once in MELE as I am waiting on a patch to hopefully drop and fix some of the bugs and power issues with Adepts. I played Infiltrator and it was pretty easy in MELE, but if you want a good view of the OE version of Vanguard then here is a video of the fight. Vanguard battle of SB in OE ME2.
Playing Mass Effect Andromeda actually helped me in this fight as it encouraged a more fluid thought on cover, instead of the more static system of ME2. Cover is what blocks shots, not something you should stick to like glue. Also having powers that stagger the SB is essential, such as warp and in OE version Singularity(haven't really had much practice in MELE so don't know how bad they nerfed it here).
