Yes, a sealed battery will stop me from buying this phone.. for a couple reasons.
1. (Personal) I hate how thin/light phones are getting today. I don't want $700 piece of technology to feel like it might shatter if I sneeze on it.
2. (Practical) Even if this phone has "Good" battery life, what that really means is "GOOD for an LTE phone".... which is still terrible amongst non LTE phones.. No LTE phone currently comes close to a full days usage off the charger without massive tweaking of features (toggling radios) and/or an extended battery.
3. (Practical, but speculative) I have, in the past 5 years, had 3 different phone batteries stop accepting charge/die before the phones they where in encountered any serious problems. A replacement battery is under $70. If this phone's battery encounters a similar issue... what then? Would I now have to replace an entire phone because of a battery? Even a best case scenario involves having to take the phone in to a technician and be potentially without a phone for days... Either way the situation is unacceptable for me as a consumer.