Its not like you need to do whole playthrough to determine is for example
Rogue Specialisation, Ninja: You are a Shinobi, a dreaded master of espionage, stealth, deception and assassination. Your exacting training grants you benefits related to your magical abilities. You receive a +2 bonus to Willpower saving throws. You get the feat Fast Spells for free at level 1. In addition, you gain one extra spell slot of each available spell level.
or
Monk Specialisation, Way Of The Candle: Your focus on pious meditation in a candlelit monastery has granted you profound insights into energy manipulation through mystical means. You receive a +1 bonus on all Damage Rolls. You also gain an Energy Shield personal-range Free Action supernatural ability, as the spell Energy Shield (Wizard). You can use this ability once per day from level 1 to 3, twice per day from level 4 to 6, three times per day from level 7 to 9, four times per day from level 10 to 12, five times per day from level 13 to 15, six times per day from level 16 to 18, and seven times per day from level 19.
as good/useful as dex to dmg. I know what those spells and feats do so I can use my imagination.
there are classes, subraces, feats and spells in same tier/school that are simply better that other options.
If you dont want to be an epic powergamer thats obviously fine but its quite retarded to assume everything is equally good.