Wrath & Glory had a rough start with its previous publisher, but I've been playing since its earliest released edition. It is at its heart, a system that accomplishes what it sets out to accomplish and has ample room for growth.
To wit: W&G is not meant to be a 1:1 replacement for its predecessor system, Dark Heresy (and its derivatives like Rogue Trader, Only War, Deathwatch). Dark Heresy was by design, intended to be an extraordinarily deep system, with little breadth. It is deep, but narrow. It is focused almost entirely on Imperium-based play, with incredibly rich descriptions of equipment and minor settings, and superlatively detailed rules for every occasion. That was both its greatest quality, and worst trait in my opinion. Every time I picked up a Dark-Heresy style sourcebook, I felt the utmost overwhelming desire to dive into the universe - to play and run its games. To absorb every rule and every nuance of the gameplay. Every time I tried to play Dark Heresy (and on other occasions, Rogue Trader), the campaigns felt flat. There was almost never a GM capable of meeting the standard of richness set by the book. Every session was bogged down by half an hour of searching for rules (and there is no reasonable way to summarise Dark Heresy's rules). I had never seen a universe so rich, and a ruleset so wretchedly bloated.
Wrath & Glory is the opposite by design, and in my play experience. W&G is by design, very shallow and very wide. Some would understandably make the same criticism for as Skyrim: a game with an ocean's width, and the depth of a puddle. This ignores that games like Skyrim are iconic in their field, and actually incredibly fun. W&G's in-house settings have never appealed to me. I have never once looked in its wargear lists and been enamoured with an item of gear or a relic. Yet the rules slipped on like a glove, from its more flawed first edition until now. In playing W&G, my groups have always been able to commit the main rules to memory, and make a reasonably sized quick-reference file for the other content. Having to trawl the rulebook for an obscure rule is fairly uncommon with this system. When I picked up Wrath & Glory and read it for the first time, I felt none of the burning desire to immerse myself the way Rogue Trader made me want to. Nothing even close. But unlike any of those previous systems, my group of newcomers and 40K lore buffs all got together and finished a long campaign. And we actually played the game successfully. That is the system's greatest success, and one I build my rating on. I can play Wrath & Glory, and it's not a chore. I can play it, and it's enjoyable. I can flesh it out with mountains of homebrew and not fear for conflict and bloat.
The comparisons between W&G and the entire Dark Heresy library are frankly unfair. Comparing a first-release core rulebook to a nearly decade-long franchise spanning dozens of works that had a completely different design philosophy is patently absurd. W&G, like Dark Heresy, needs to be evaluated on its own merits as much as its own drawbacks. The result is that I see W&G for what it was meant to be: a contemporary introduction to 40K roleplay suitable for new and old people. One that is not gated behind the elitism, expense and complexity of Dark Heresy, but one that consequently lacks fleshing-out.
The core mechanic for W&G is simple, adaptable and has built-in nuance for catastrophic and exceptional results. It is a generally stable and useful core mechanic using pooled D6 and I find it excellent. It does suffer from scaling issues when tests or skills become too high, and it is very difficulty to accurately estimate percentage changes for your success, unlike D20 or D100 systems.
Lore wise? My group are consummate homebrewers. We did not play with the pre-packaged lore for this one just like all the Dark Heresy and Rogue Trader source materials. I read those works for entertainment and inspiration, not to build a campaign over. From what I read of this book's lore, it is basic and covers the essentials, but it suffers from the shortcoming of having to place too many species into too-small a setting, and suffers from a lack of depth.
The lack of content with regards to wargear, narrative impact and playable characters is the book's greatest limitation. The book is packaged for four distinct factions (Orks, Eldar, Imperial, Chaos) right out of the box. But you can only play a very limited and small version of all of those factions except for the Imperium (unsurprisingly). Even the Imperial selection of wargear is pedestrian and basic by Warhammer 40 000's standards, with none of the eye-popping innovation and complexity previous systems featured. The gear and character archetypes require future content support, or heavy GM homebrew to reach their potential. Yet like every other part of the system, the framework for designing your own equipment and archetypes are simple and straightforward.
Cubicle7's changes in formatting, talents, ascension packages and... spelling are generally positive. I have no areas to report where the earliest edition was clearly superior to this edition and I write this on the release of its 2.1 Errata, adding new corrections and adjustments. I do note the removal of vehicle combat and voidship combat rules from the previous edition. I respect Ulisses' attempt for bringing iconic voidship combat into this system, but the attempt to bring such a complex and rich set of rules to a streamlined system was unsuccessful. The original implementation of vehicle and voidship combat were some of my greatest criticisms and Cubicle7 has seemingly removed them outright. Sadly, I think the removal of this content improved the average quality of the work, but it is notable.
++Superbly simple and adaptable ruleset
+Much better organised than previous edition, may Ulisses North America do well for the work they put in
+An excellent base for future content additions
--Very shallow on its own story, gear and lore, requiring copious future content updates or copious homebrew
-Depth of rules was sacrificed in favour of flexibility and playability
-Removal of the vehicle combat rules, even if they were hideously flawed
A 4/5 in my eyes, if you want to play a 40K RPG. A 5/5 if you have a GM willing to do the copious homebrew needed to flesh it out. And a 5/5 one day, if it receives the content support it deserves.