I find it interesting that some are concerned with there being trap choices in wizard spells. I've always felt the uncertainty involved in spell preparation is part of the fun of playing a Vancian caster. Even some of the mainstay spells, like fireball, are situational due to potential consequences.
D&D Next gives wizards some decent at-will spells to round out the rough edges, and rituals provide even more of a safety net. Further siloing would only harm the last vestiges of the Vancian risk/reward system.
However the number of spells has been cut drastically. By mid-high levels in 2E and 3E, there was no risk/reward because of the vast number of spell slots available and the ability to make spell scrolls/wands/etc. Therefore, magic users were reward/reward - vast flexibility, with almost infinite access to every important spell.
At the moment, the number of spells is highly limited, and it looks like a 10th level wizard might have access to ~15 spells overall (compared to probably 25-30 or more (depending on how big of a scroll/wand collector they are) in 2E/3E.
Given that they're drastically limiting the number of spell slots and metagamey mechanics that allow access to less commonly used spells, doesn't it make sense to allow rituals? I mean if you're sacrificing 1 spell slot in 30 for a limited use spell, that's one thing. If you're sacrificing gold for 1 spell scroll you have a 3% chance of needing that's another.
When you're sacrificing 1 spell in a small handful with no spell scrolls available, well... that's quite the thing. Ritual magic just makes sense.