You have some freedom in available builds, but not much. Each level you're given two points to increase a skill (at one point cost) or learn a new skill (at two points cost). If you want to increase the higher-tier skills, there related lower-tier skills have to have the same or a great level. To increase archery to level 2, you have to increase blade and path of the shield to two. The middle, "power" branch always has to be upped – which works because they consist of essential passive skills – before you increase the more offensive battle or more supportive utility branch, both of which allow you to unlock more and more useful skills. The system doesn't lack in providing interesting skills to use in combat, but it does limit you to either generalizing in all branches or specializing in power or utility. Specializations, which you unlock three times, add no real variety as they are just +1 bonuses to each skill of the branch rather than additional unique options.
This doesn't sound ideal to me, but for a good part is is a tradeoff. For one, this class system means leveling up feels significant, as each level up can unlock a new skill or ability. For another, it allows the develop to focus on balancing, with no class or skill being overpowered. The real problem appears with the followers. You have four followers in the game, none of whom are recruited in an interesting sequence, instead they are dumped on you in pairs early in the game. This kind of defeats part of the function of having followers instead of party creation, but they do offer a lot of commentary during the game, and each has a loyalty mission that is triggered at specific points during the main quest, each of which is set up to reveal more about the game world. They each have a specific function in the game's story, and like much of the game's narrative that part of it works very well.
It is the character system part of it that doesn't work as well. If one would compare it to Mass Effect, which similarly has two followers you can take along while the rest stay home and still level up somehow, the followers there aren't as big an issue because they don't resemble the class archetype purely, instead they have unique skills and more options for builds not open to Shepard. In Avadon, each follower is identical to the PC of the same class, in fact they look exactly the same except for some pallet swapping and different portraits. This means you can try almost every party build and certainly every character build in one playthrough. Heck, if you want to experiment, the game even has a freely available respec option a ways into the main plot.
I can't say I ever put much value to Spiderweb games specifically for their replayability, but the Avernum and Geneforge titles were very open for variety both in gameplay choices and character or party builds. Avadon has none of this. The sequence of quests and unlocking areas are always the same no matter what choices you make, while I discovered very soon in my second playthrough how discouraging the character system is. What's the point of playing as a blademaster when I already had a blademaster with exactly the same character build capabilities in my party last time? To put it bluntly, I feel this combination of simple character system, respeccing and four followers matching the classes were simply a mistake, and strongly hope future Avadons have a more complex character system and more interesting, unique followers.
Combat and Difficulty
With so many combat-focused skills, it is not surprising that combat is a major part of the game on top of dialog and exploration. Like the game's interface, combat will feel instantly familiar to Spiderweb fans. It is a top-down, turn-based affair where each combatant moves in a sequence determined by their agility stat. The PC and his followers can use close combat or ranged weaponry – including magical staff attacks for the sorceress or druid, which use no resources – or a variety of special skills and items. Enemies too have a range of basic and special attacks to their disposal, including a lot of spells and summoning abilities for the unique fights.
I'm a big fan of turn-based combat in games with parties or followers under the PC's control, and the basics work as well in Avadon as in any Spiderweb game. Jeff Vogel has steadily learned a lot about combat design, with regular but not overly large amounts of trash combat interspersed with interesting encounters and boss-fights, set up to play out as unique fights. Reminiscent of the latter Avernums, some of these get a bit gimmicky and need to be approached in a specific way decided by the designer. But even the gimmicky ones remain unique and interesting. Like his preceding titles, Avadon shows Spiderweb learned a lot about combat spacing and encounter design, and to me combat never felt like a slog through mob upon mob, like many RPGs – turn-based or otherwise – often suffer under.
That said, the tendency towards accessibility rears its head once more here. I'm usually not that skilled at tactics-heavy RPGs, but even for me "normal" seemed more like easy. Jeff Vogel himself noted himself, he's aiming at a normal difficulty that allows 90% of the players to finish, but I'd be surprised if as much as 10% would have much difficulty with this game on normal. Like most of his titles, Avadon spikes in difficulty late into the game, when the player should be more familiar with the system and have powerful builds. And even on normal there were certain fights at the very end that I found needed some attempts to pass without using up too much vitality or items. But still, this game suffers some under the "normal is the new easy"-standard that is prevalent through much of the mainstream industry, and I can imagine hard or even torment being a more suited setting for the audience Spiderweb games usually attracts. But that's fine, you can change them at any point in the game.