I am much more friendly to Dark Age fiction that most, mostly because it was the Wizkids clicky game that got me and my friends into the Battletech universe. I own a bunch of the earlier novels and while I won't defend them just for the sake of my adolescence, I do think several things need to be kept in mind.
The first ten or so novels are all in a very small timeframe, and focus on the small picture. The HPG system has been struck down by mysterious assailants, and many of the first few novels deal with characters and planets reeling in the aftermath of such a chaotic situation. No one in the first many novels really is in a position to investigate exactly who shut them down, especially since communication between planets is now restricted mostly to jumpships and the few HPGs that managed to stay up (Archenar, the planet of the second novel, has a surviving one, same with Ronel and Tigress). That said;
In the first novel "Ghost War" the main characters are all Republic Knights and soldiers, and they do have several chapters dealing with who shut down the HPG, and how much they know. At this stage in the game, what they know isn't much, so the majority of the book does not deal with that. G.W. has some pretty good action scenes and honestly sets up what will define the first few years of the Dark Age era; The Republic is floundering with communication, factions based on loyalty to the Great Houses or Clans are rising up, and even local governors or family scions (the nobility, which were supposed to be neutered by the Republic and Stone) are making power grabs in the chaos. It's an interesting scenario, if small-scale.
On top of this, you do have one of the big design decisions of the Dark Age era; an attempt to return to the feeling of the 3025 era by making Battlemechs more rare and awe-inspiring. Most of the early novels keep to this theme, some to their advantages and others not. "A Call to Arms" has the milita on Archenar have only 1-2 mechs, making the Steel Wolf invasion of that planet that much more threatening since they have about a Star of Clan Mechs. Meanwhile, the "Proving Grounds" trilogy is laughably unrealistic when the Steel Wolves (This time under Anastasia Kerensky) invade Terra with a lance (The writer of the trilogy understood very little about the Battletech universe, least of all Clan military breakdowns) and are considered nearly unstoppable. While the design decision to make Battlemechs more rare in the Dark Age may seem inconsistent with Battletech (which is at its core a game about giant robots beating the crap out of each other),for the setting, it makes sense. The Jihad was supposed to be a very devastating conflict, on the scale of the Succession Wars, with all the nukes and biological weapons the Word of Blake was throwing around. Combine the destruction of much infrastructure of the Inner Sphere, their decimated militaries, and the fact that Devlin Stone, the only man able to wrangle together a coalition capable of pushing back the Word of Blake, was holding most of the military of the Inner Sphere in his pocket and had a hankering for demobilization, it's not hard to see the Inner Sphere going along with his line, willingly or not. And most of the Houses (with exception to Liao) did go along willingly, what with that whole weariness thing up above.
The quality of the novels after Proving Grounds does take an appreciable upturn, "By Temptations and By War" and "Fortress of Lies" are the beginning of the massive Liao incursion into the Republic and their fight against the Swordsworn, and have a lot of character conflict and personality. The Jade Falcon invasion books, which were some of my favorites, have... understandable Clan characters. Let's be honest here, the Clan way of upbringing children is going to result in very few "well-adjusted" persons (from our perspective). That the all of them aren't crazy and sociopaths is surprising. Add in 70-odd years of the Clans being unable to do more than conduct small-scale raids, when the whole point of their society and conditioning was to get them ready to take back Terra and restart the Star League, it's understandable to think some of their members would become even more deranged and violent. Clans have never been "knights of yore", no matter what kind of "honor" they talk about. Their whole way of life is about waging war, and now some of their characters are just more honest about it.
It's with these novels as well that the beginning theme of the Dark Age changes; from being focused on the small-scale to growing to include the rest of the Inner Sphere, piece by piece. House Liao is introduced in 7 and 8; Jade Falcon and House Steiner (sort of) in 10 and 11, in 14-18 you get nearly every Great House and Clan. Every group gets at least 1 or 2 characters in "Sword of Sedition", and they are all very enjoyable to read and see interact. The conflict expands as well, as Liao fights the Republic and probes Davion, Kurita invades the Republic, and civil war begins to develop in the Republic (and groundwork is laid for another one in the Federate Suns). The action expands with the cast of characters; companies of mechs are seen on either side along with vehicles and infantry. This is, with a few exceptions, where my reading ended with the Dark Age novels (since it became harder and harder to find them in-store).
I should mention that Novel 19, Blood Avatar, does have a good bit of detail about the HPG sitaution, if you can deal with a Battletech novel that does not have a single mech fight in it. I heard it's a very good detective story though.
I think Wizkids mostly wanted to start off M:DA very slowly so that new fans could jump into the game and not be overwhelmed with source material and multiple factions. That the beginning factions all had the same basic premise (all splinter sectarian groups) while also tying themselves to older and established factions was an interesting story tool, even if it alienated a lot of the established battletech community. If Mechwarrior had remained a successful property, it would have been neat to see where the Dark Age was going, but unfortunately now it will have to wait until Catalyst catches everything up with it.