Distributed Key Generation (DKG) is crucial for initializing threshold cryptosystems without a trusted third party. However, adapting DKG to asynchronous networks (i.e., ADKG) presents challenges. In this paper, we address two: (i) fixed threshold, where each set of \(t+1\) participants is identical, lacking the flexible configurations needed for asynchronous environments; and (ii) high complexity, which arises from the use of multiple parallel instances during the consensus phase. We propose FlexiADKG, an ADKG protocol that features a configurable threshold structure and reduces communication overhead. By utilizing vector space-based secret sharing, FlexiADKG enables customizable threshold configurations based on node-specific attributes such as reputation and security level. Additionally, we replace traditional n parallel asynchronous binary agreement (ABA) instances with a multi-valued Byzantine agreement (MVBA), thereby reducing round complexity from \(O(\log n)\) to O(1). We implement FlexiADKG on geographically distributed AWS instances and evaluate its performance with node sets of 16, 32, 64, and 128. Experimental results demonstrate that FlexiADKG significantly outperforms the ADKG protocol by Das et al. (SP’22), achieving 61% of the runtime and 53% of the bandwidth consumption on average. We also provide formal security proofs to validate all claimed properties.