Is sphere arcanist closer to a wizard than a sphere wizard?

[noob]

I mean the sphere arcanist get to swap his spheres and talents every day while the sphere wizard have no possibility to change his spheres once he picked them up.
The reason why the sphere arcanist prepare his spheres while the sphere wizard just is a slight variant of the main sphere caster is completely unknown to me.
Can someone explain me why is the sphere wizard identified as an adaptation of the wizard while the sphere arcanist is not?

[Segev]

For whatever reason, the Sphere Wizard is actually just the Sphere Caster with a few of its options pre-selected. You can literally build a Sphere Wizard using the Sphere Caster chassis. I don't know why the choices made for Sphere Arcanist were made.

[EldritchWeaver]

For whatever reason, the Sphere Wizard is actually just the Sphere Caster Incanter with a few of its options pre-selected. You can literally build a Sphere Wizard using theSphere Caster Incanter chassis. I don't know why the choices made for Sphere Arcanist were made.

Spherecaster is a general term for an magic user which employs SoP. Regarding OP's question: Purely speculative, but the incanter (which is the wizard-like archetype realized with the SoP system) was supposed to play well with the magic system introduced in this book. Aside from the Spirtualist Hedgewitch, all classes/archetypes are fixed talent casters. In general, the trade-off is that you trade flexibility for staying power, which means that completely flexible casters were contrary to the design goals.

Fast forward to the archetype conversions. The arcanist is a spontaneous caster, who can switch the spells he uses. That is basically what the wizard would be after the conversion to SoP, if he had kept the ability to switch talents. Now this conundrum leaves two options. The first one is to have an arcanist, which is basically an incanter, with exchanging the incanter class features with the arcanist's one. This would be so close to the design space of the incanter, that this effectively could be better solved with the exploiter archetype translated to incanter. It also ignores the main shtick of the arcanist. The second one is two allow switching talents once per day. That it faithfully replicates the arcanist's shtick causes no the problem that it outperforms the incanter. Which is the reason why the number of overall talents is low and why the flexible talents are restricted to arcanist class levels to keep at least a semblance of balance.

This means that the sphere arcanist is in an odd place. If the original SoP would have kept at least for one class the talent switching ability, it would have been realized as an exploiter-like archetype for this class instead of converting the class itself. As it didn't, it can be argued that the sphere arcanist is closer to what the incanter should have been than what the wizard-like class is currently now. It is such an oddity, that it could be argued that it shouldn't be included in the game or that it base mechanics are desirable enough that at least some full-casters should be like this.

[Dr_Dinosaur]

The Arcanist was the Wizard with actual class features, so when converting them over one becomes what might be expected from a "Sphere Wizard" while the other is a painfully generic high caster, just like before.