...encompass all you'll ever want out of a sneaky trickster/illusionist/mindbender archetype.
Don't generalize. I've had enough people saying I
shouldn't play this and that class combination, because there is a class who already does it, and statements such as the above encourage the line of thinking. The Beguiler is a kind of trickster. A good one, but not all of them at once. The difference between Beguiler list and Beguiler list is literally five spells over the course of twenty levels. Let's take a look at this Illusionist. Granted, they have some spells in common. Cantrips, mostly. But Illusory Script? Not a Beguiler spell, damned if I know why. Phantasmal Strangler? Not on the list. Retributive Image? Nuh-uh. Nightmare Terrain? Nope(Though that may be for the better). Shadow Well? Guess. Listening Lorecall? I can't even take the thing through Advanced Learning, but damn, in retrospect the Beguiler would love it. And we've already run out of customization options. Let's skip all the echantments they are missing out on, and the part where I point out why you may not want Silent or Still Spell at all.
In the end, whereas a Beguiler is easy on you and reliable as you said, it falls behind in versatility compared to classes who are allowed to cherry pick their spells and bonus feats. Moreover, they are anything
but easy to play. The Beguiler doesn't so much offer room for creativity. It expects you to have some. And when you've run out, tough luck. You're dead.
Even if your save DCs are ridiculous, you still need to give a thought how and where to cast a figment, what orders to give through your compulsions, who and when to charm, or your targets
will figure out what you're up to. That's not a lack of imagination, just plain human error: happens to the best of full casters every once in a while. Unlike the best of us however, Beguilers have precious few options for a contigency plan.
Not to mention, the class structure assumes you're always on your guard, to prevent other people from finding out you're a Beguiler. Fail to cast your Abjurations when you'd need them just once, and you've effectively lost half your power for the rest of the encounter. Big risk, for a mediocre payoff. And it's not as if Beguilers aren't aware of that weakness. Detect Magic, True Seeing, Telepathic Bond... They are prepared to counter another trickster themselves, even though by definition they know how tricksters think. By believing a Beguiler's life is easy, a Beguiler probably isn't going to hold his ground unless given a healthy dose of harsh life lessons.
