High School DxD Hero: Taiikukan-ura no Holy

I will be subjective here, because comparing rework of the episode ( few changes) can be done subjectively only.
Since this is only one episode I will be rating it differently and tell you why the original Juggernaut ( I know it was non canon) was better by my thoughs. There are quite a bit of changes so let's go.

Juggernaut: I'll split it into three phases: begining phase, fight phase and "Aftershalba " phase.
1st phase: Issei getting into Juggeranut. I think BorN did this transition way more intense than this rework so here BorN wins.
2nd phase: Issei fight with Shalba. I think both are epic so ... I'll leave it at draw.
3rd phase: Here comes the funny part, BorN 3rd phase is mainly non canon, we see Issei fighting with Vali in his Juggernaut drive to weaken Issei berzerk, after using Divide Rias come and try to awaken Issei which eventually happens. Now the Canon one, Odin sends a radio with Oppai dragon song which our protagonist play to Issei which leads to his return to normal, good way to ruin a serious moment. I'll give it to BorN. Even though it's not canon I liked overally fight and serious ending better, this also can be used as a stop of DxD being a little bit of horror themed.

Why it's getting 7/10 while BorN was 6/10? Because there are some added scenes like Cao Cao scene for example, which looked really sick

Little after edit: Overall I think this was unnecessary episode, I would rather see rating game: Rias vs. Sona

The biggest issue I had with this remake is that most of the main cast got redrawn slightly goofy. As if this was a Saturday morning cartoon like Tiny Toons.

This very noticeable in how the hair and eyes are drawn for all the characters. Hair that used to have dimension is now just someone doing a flood fill in MS Paint. Rias' and Akeno's hair no long flows they might as well be hard plastic wigs.

Heck Rias' hair is no longer crimson, it's just fire engine red. Once silver hair is now dull light gray.

The animation is much more ... simplistic as well. When people turn their heads their hair swivels with them instead of flowing as it should.

some minor DxD Born spoilers are included in this Review

First, I want to give advice to anyone who've watched DxD Born and satisfied with it, you should SKIP this episode, just go to first episode of DxD Hero, there will be animation difference you'll either content or disappointed. But plot-wise, I don't think we need this episode as "bridge", we can continue into 4th season(DxD Hero) with final Born memories in mind.

Story:
As I stated above, this one is has some differences from final 4-episodes of DxD born but I think it's unnecessary. Main difference is Rias 'Arc' that's completely removed. I don't read the ... LN, so I don't know the reason, but to us who've watched Born, we can't just erase it from our memory, right? The other major difference is how they resolve Issei rampage, and I would say this with 100% confidence, how DxD Born resolve that is ten times better than this. How could you change beautiful moment into silly joke? I don't care even if that's deviation from Novel, I still think it's unnecessary to create special episode for this crap.

Art:
Different studio handle 4th season including this, it's not unusual if they want to change art and animation style. I don't really want to complain, as mostly it change into lighter tone but at least they're still recognizable. BUT.. the one that I won't accept, and probably stay the same for entire 4th season is.. Rias Appearance. What a terrible things they did to the mature, elegant, beautiful looks of our Ruin Princess, they completely ruin it (no pun intended). And here, they change her into cliche cute and plump girl. Usually I like those kind of character art, but for Rias, that's complete bust of character. And I need to endure it for this and next installation of DxD?

So to summarize this, I won't recommend this episode for DxD anime fans (anime-only, as LN reader would have different perspective). That recommendation also applied to those who are completely new to DxD series (are they even exist?), they would need to watch the first 3 season anyway, and that's from different studio, result in different art style and plot, like it or not.