A rule-builder and SmartApps are not mutually exclusive. As mentioned in various other threads we plan to have both. Some SmartApps are and will be much too complex to build using a rule-builder. In fact, as soon as you get past basic nesting and conditional logic the integration face becomes c meets one in many cases. We are still working it but there is a reason it is IFTTT.com and not IFTATBNT.com (if this and this but not that).