Well, the idea behind scribing your scrolls is to not be stuck without an important spell because you memorized the wrong thing today.
With that in mind, you'd only really scribe scrolls of the spells you'd find useful in a key situation, but is otherwise useless the rest of the time.
So, don't think of things like making scrolls of magic missile "to have more blasting power per day". Rather think of things like Comprehend Languages or Floating Disk. The power is in keeping your versatility.
Wands are far better for "need more power". 750gp for 50 charges instead of 25gp for one charge... it's simply more economical for something you are going to repeatedly cast over and over.
Note, that's 7.5gp vs 12.5gp per charge if you are crafting them yourself, although you would have to get the Craft Wand feat if you plan on doing that.
The actual process for crafting is as follows:
- Pay the cost of the scroll. This is half the base price of the item, plus any material components.
For a first level scroll, that's 12.5gp.
- Find the DC to create the scroll. Normally this is 5 + caster level. You can double the speed of creation by adding 5.
So a first level scroll at caster level 1, done at double speed, the DC is 11.
- Spend the time creating the scroll. Normally this is a minimum of 8 hours, but potions and scrolls can be as low as 2 hours (if less than 1000gp). For example, a 500gp scroll would take 4 hours, while a 250gp scroll will take the 2... since the minimum is 2 hours, anything less than 250gp still takes the 2 hours.
If you accelerated the crafting, it'll only be 1 hour.
If you are adventuring, you can only apply 2 hours of crafting per day (and it takes 4 hours of your down time to get that 2 hours in).
Since you only need 1 hour to make that first level scroll, you can spend 2 hours crafting during adventuring.
- Roll your Spellcraft check. Success means you made the scroll. Failure means you wasted your time and money.
- That's it. You can only make one magic item per day, even if you have extra time leftover that you could have made another item with. One scroll per day.
If you scribed a lot of utility spells into your spellbook, or picked a bunch for your first level spells, then it's a good idea to make some of them into scrolls so you don't have to waste spell slots on them that might never get used.
Better to leave yourself Enlarge Person or Color Spray in your spell slots, because when combat happens, you are likely to use them. That one time that Erase might come in handy, you don't have to have to wait for 24 hours to get access to it.
Although, something to keep in mind as well is you can leave spell slots open to be memorized later. As long as you don't mind not having it for combat, you only need to spend 15 minutes (or so, depending on how many slots you left open) to memorize a spell before using it.
Keeping a slot open per spell level for a utility spell can be handy, although it does mean it's not available for at least 15 minutes.
Lastly, regarding the "viability" of Wizards: they are as much viable in Pathfinder as they were in 3.5e. In other words, they can dominate the game, given the right access to spells.
The only real difference between 3.5 and Pathfinder is that it's now viable to
stay in the class instead of multiclassing into a Prestige Class. Arcane Bond with an object gives a nice alternative to the familiar, and every school (including Universalist) gives neat abilities that scale with level.
Plus, Pathfinder has moved the Archmage abilities into feats instead of keeping the class, so it's more worthwhile to just stick with the Wizard to level 20 and pick up the metamagic and spellcasting feats to get the neat spellcasting stuff you wanted.
Anyways... I hope this helps!