ParcLife isn't that far away, but the proposed temple and industrial buildings nearby will drive away investor-type buyers for sure.
My guess is that there will only be 3 pricing types:
1) Pricing higher than Brownstone - (very unlikely)
This will mean Huat Ah for Brownstone Resident. Haven't move in, your property price increase le. Will help to move Brownstone sales even faster. If really so, Visionaire's sale will be rather slow, made worse by their bigger unit which mean each unit will cost higher due to more psf
2) Pricing lower than Brownstone (unlikely)
Profit already rather low for EC. And they paid slightly higher for the land. Underground carpark and SMART concept further eat into their profit. 2 clubhouse too brings the cost higher too. 6 units lesser than Brownstone mean lesser profit. Bigger unit mean less profit too as usually smaller unit commands higher price psf. Bad for Brownstone resident as price drops already lower before shifting in and affect also affect the sale of Brownstone's remaining units.
3) Price about the same as Brownstone or slightly lower (Likely)
Give buyers an impression that they are getting a lot more than Brownstone at the same price although Brownstone will still be nearer to the MRT. Buyers will be split between the 2 ECs. More will move to buy Visionaire as they can still choose their choice unit. Brownstone is not able benefit at this pricing. Neutral effect on Brownstone resident.
Nevertheless, don't give too high expectation that Visionaire's pricing will be comparable to Parc. Visionaire bids the land at $352 psf while Parclife bids the land at $320 psf. There is a significant difference in the land price. If Visionaire is priced low with so many additional cost, you should need to worry abut its quality since the profit margin for EC is already rather low...