When the reality is, it is not at all unusual for a cRPG to be designed with a specific set of levels in mind, just as p&p modules often have a specific set of levels in mind.
Since i have played paper RPGs as well I know what you mean. Not an issue by itself (I haven't called a lv10 cap an "issue"). Having played dozens CRPGs as well and almost all DND-based ones I have the feeling how LONG does it takes to reach that goal. So my disappointment is for a game SHORTER overall than just for the level cap.
Of course it is speculation as this point (cant play the beta RN), and maybe the devs diluted XP so much that Solasta will lasts for 40+ hours. But I bet it wont.